[[Image:Splash-prop.jpg|right|720px]]<strong><font color="#4e1985" size="4">True 3D, Coherent, Polarimetric Ray Tracer That Simulates Very Large Urban Scenes In Just Few Minutes!</font></strong><table><tr><td>[[image:Cube-icon.png | link=Getting_Started_with_EM.Cube]] [[image:cad-ico.png | link=Building_Geometrical_Constructions_in_CubeCAD]] [[image:fdtd-ico.png | link= An EM.Terrano Primer Tempo]] [[image:static-ico.png | link=EM.Ferma]] [[image:planar-ico.png | link=EM.Picasso]] [[image:metal-ico.png | link=EM.Libera]] [[image:po-ico.png | link=EM.Illumina]]</td><tr></table>[[Image:Tutorial_icon.png|30px]] '''[[EM.Cube#EM.Terrano_Documentation | EM.Terrano Tutorial Gateway]]'''
=== Modeling Wireless Propagation===Â Every wireless communication system involves a transmitter that transmits some sort of signal (voice, video, data, etc[[Image:Back_icon.), a receiver that receives and detects the transmitted signal, and a channel in which the signal is transmitted into the air and travels from the location of the transmitter to the location of the receiverpng|30px]] '''[[EM. The channel is the physical medium in which the electromagnetic waves propagate. The successful design of a communication system depends on an accurate link budget analysis that determines whether the receiver receives adequate signal power Cube | Back to detect it against the background noise. The simplest channel is the free space. Real communication channels, however, are more complicated and involve a large number of wave scatterers. For example, in an urban environment, the obstructing buildings, vehicles and vegetation reflect, diffract or attenuate the propagating radio waves. As a result, the receiver receives a distorted signal that contains several components with different power levels and different time delays arriving from different anglesEM.Cube Main Page]]'''Â The rapid growth of wireless communications along with the high costs associated with the design and deployment of effective wireless infrastructures underline a persistent need for computer aided communication network planning tools. The different rays arriving at a receiver location create constructive and destructive interference patterns. This is known as the multipath effect. This together with the shadowing effects caused by building obstructions lead to channel fading. The use of statistical models for prediction of fading effects is widely popular among communication system designers. These models are either based on measurement data or derived from simplistic analytical frameworks. The statistical models often exhibit considerable errors especially in areas having mixed building sizes. In such cases, one needs to perform a physics-based, site-specific analysis of the propagation environment to accurately identify and establish all the possible signal paths from the transmitter to the receiver. This involves an electromagnetic analysis of the scene with all of its geometrical and physical details. ==Product Overview==
===EM.Terrano in a Nutshell ===
EM.Terrano is a physics-based, site-specific, wave propagation modeling tool that enables engineers to quickly determine how radio waves propagate in urban, natural or mixed environments. EM.Terrano's simulation engine is equipped with a fully polarimetric, coherent 3D ray tracing solver based on the Shooting-and-Bouncing-Rays (SBR) method, which utilizes geometrical optics (GO) in combination with uniform theory of diffraction (UTD) models of building edges. EM.Terrano lets you analyze and resolve all the rays transmitted from one ore more signal sources, which propagate in a real physical site channel made up of buildings, terrain and other obstructing structures. EM.Terrano finds all the rays received by a receiver at a particular location in the physical site and computes their vectorial field and power levels, time delays, angles of arrivaland departure, etc. Using EM.Terrano you can examine the connectivity of a communication link between any two points in a real specific propagation site.
=== Line-Since its introduction in 2002, EM.Terrano has helped wireless engineers around the globe model the physical channel and the mechanisms by which radio signals propagate in various environments. EM.Terranoâs advanced ray tracing simulator finds the dominant propagation paths at each specific physical site. It calculates the true signal characteristics at the actual locations using physical databases ofthe buildings and terrain at a given site, not those of a statistically average or representative environment. The earlier versions of EM.Terrano's SBR solver relied on certain assumptions and approximations such as the vertical plane launch (VPL) method or 2.5D analysis of urban canyons with prismatic buildings using two separate vertical and horizontal polarizations. In 2014, we introduced a new fully 3D polarimetric SBR solver that accurately traces all the three X, Y and Z components of the electric fields (both amplitude and phase) at every point inside the computational domain. Using a 3D CAD modeler, you can now set up any number of buildings with arbitrary geometries, no longer limited to vertical prismatic shapes. Versatile interior wall arrangements allow indoor propagation modeling inside complex building configurations. The most significant recent development is a multicore parallelized SBR simulation engine that takes advantage of ultrafast k-Sight vsd tree algorithms borrowed from the field of computer graphics and video gaming to achieve the ultimate speed and efficiency in geometrical optics ray tracing. Multipath Propagation Channel ===
In a free-space line-of-sight (LOS) communication system, the signal propagates directly from the transmitter [[Image:Info_icon.png|30px]] Click here to learn more about the receiver without encountering any obstacles (scatterers). Free-space line-'''[[Basic Principles of-sight channels are ideal scenarios that can typically be used to model aerial or space communication system applicationsSBR Ray Tracing | Basic SBR Theory]]'''.
Click here to learn more about the theory of a <table><tr><td> [[Free-Space Propagation ChannelImage:Manhattan1.png|thumb|left|420px|A large urban propagation scene featuring lower Manhattan.]].</td></tr></table>
[[Image:multi1_tn=== EM.png|thumb|500px|A multipath propagation scene showing all the rays arriving at a particular receiver.]]In ground-based systems, the presence of the ground Terrano as a very large reflecting surface affects the signal propagation to a large extent. Along the path from a transmitter to a receiver, the signal may also encounter many obstacles and scatterers such as buildings, vegetation, etc. In an urban canyon environment with many buildings Propagation Module of different heights and other scatterers, a line of sight between the transmitter and receiver can hardly be established. In such cases, the propagating signals bounce back and forth among the building surfaces. It is these reflected or diffracted signals that are often received and detected by the receiver. Such environments are referred to as âmultipathâ. The group of rays arriving at a specific receiver location experience different attenuations and different time delays. This gives rise to constructive and destructive interference patterns that cause fast fading. As a receiver moves locally, the receiver power level fluctuates sizably due to these fading effectsEM.Cube ===
Link budget analysis for a multipath channel EM.Terrano is a challenging task due to the large size ray tracing '''Propagation Module''' of the computational domains involved'''[[EM. Typical propagation scenes usually involve length scales on the order of thousands of wavelengths. To calculate the path loss between the transmitter and receiver, one must solve MaxwellCube]]'''s equations in an extremely large space. Full-wave numerical techniques like the Finite Difference Time Domain (FDTD) method, which require a fine discretization of comprehensive, integrated, modular electromagnetic modeling environment. EM.Terrano shares the computational domainvisual interface, 3D parametric CAD modeler, are therefore impractical for solving large-scale propagation problems. The practical solution is to use asymptotic techniques such data visualization tools, and many more utilities and features collectively known as SBR, which utilize analytical techniques over large distances rather than a brute force discretization [[Building_Geometrical_Constructions_in_CubeCAD | CubeCAD]] with all of the entire computational domain[[EM. Such asymptotic techniques, of course, have to compromise modeling accuracy for Cube]]'s other computational efficiencymodules.
=== The SBR Method ===With the seamless integration of EM.Terrano with [[EM.Cube]]'s other modules, you can now model complex antenna systems in [[EM.Tempo]], [[EM.Libera]], [[EM.Picasso]] or [[EM.Illumina]], and generate antenna radiation patterns that can be used to model directional transmitters and receivers at the two ends of your propagation channel. Conversely, you can analyze a propagation scene in EM.Terrano, collect all the rays received at a certain receiver location and import them as coherent plane wave sources to [[EM.Tempo]], [[EM.Libera]], [[EM.Picasso]] or [[EM.Illumina]].
EM[[Image:Info_icon.Terrano provides an asymptotic ray tracing simulation engine that is based on a technique known as Shooting-and-Bouncing-Rays (SBR). In this technique, propagating spherical waves are modeled as ray tubes or beams that emanate from a source, travel in space, bounce from obstacles and are collected by the receiver. As rays propagate away from their source (transmitter), they begin png|30px]] Click here to spread (or diverge) over distance. In other words, the cross section or footprint of a ray tube expands as a function of the distance from the sourcelearn more about '''[[Getting_Started_with_EM. Cube | EM.Terrano uses an accurate equi-angular ray generation scheme to that produces almost identical ray tubes in all directions to satisfy energy and power conservation requirementsCube Modeling Environment]]'''.
When a ray hits an obstructing surface, one or more of the following phenomena may happen: # Reflection from the locally flat surface# Transmission through the locally flat surface# Diffraction from an edge between two conjoined locally flat surfaces Click here to learn more about the theory of [[SBR Method]]. === Pros and Cons Advantages & Limitations of EM.Terrano's SBR Solver ===
EM.Terrano's SBR simulation engine utilizes an intelligent ray tracing algorithm that is based on the concept of k-dimensional trees. A k-d tree is a space-partitioning data structure for organizing points in a k-dimensional space. k-d trees are particularly useful for searches that involve multidimensional search keys such as range searches and nearest neighbor searches. In a typical large radio propagation scene, there might be a large number of rays emanating from the transmitter that may never hit any obstacles. For example, upward-looking rays in an urban propagation scene quickly exit the computational domain. Rays that hit obstacles on their path, on the other hand, generate new reflected and transmitted rays. The k-d tree algorithm traces all these rays systematically in a very fast and efficient manner. Another major advantage of k-d trees is the fast processing of multi-transmitters scenes.
It is very important to keep in mind that SBR is an asymptotic electromagnetic analysis technique that is based on Geometrical Optics (GO) and the Uniform Theory of Diffraction (UTD). It is not a "full-wave" technique, and it does not provide a direct numerical solution of Maxwell's equations. SBR makes a number of assumptions, chief among them, a very high operational frequency such that the length scales involved are much larger than the operating wavelength. Under this assumed regime, electromagnetic waves start to behave like optical rays. Virtually all the calculations in SBR are based on far field approximations. In order to maintain a high computational speed for urban propagation problems, EM.Terrano ignores double diffractions. Diffractions from edges give rise to a large number of new secondary rays. The power of diffracted rays drops much faster than reflected rays. In other words, an edge-diffracted ray does not diffract again from another edge in EM.Terrano. However, reflected and penetrated rays do get diffracted from edges just as rays emanated directly from the sources do.
== Anatomy Of <table><tr><td> [[Image:Multipath_Rays.png|thumb|left|500px|A Propagation Scene ==multipath urban propagation scene showing all the rays collected by a receiver.]]</td></tr></table>
A typical propagation scene in [[== EM.Terrano]] consists of several elements. At a minimum, you need a transmitter (Tx) Features at some location to launch rays into the scene and a receiver (Rx) at another location to receive and collect the incoming rays. A transmitter and a receiver together make the simplest propagation scene, representing a free-space line-of-sight (LOS) channel. A transmitter is one of [[EM.Cube]]'s several source types, while a receiver is one of [[EM.Cube]]'s several observable types. A simpler source type is a Hertzian dipole. A simpler observable is a field sensor that is used to compute the electric and magnetic fields on a specified plane.Glance ==
An outdoor propagation scene may involve several buildings (modeled as impenetrable surfaces) and an underlying flat ground or irregular terrain surface. An indoor propagation scene may involve several walls (modeled as thin penetrable surfaces), a ceiling and a floor arranged according to a certain floor plan. You can also build mixed scenes involving both impenetrable and penetrable blocks, possibly along with irregular terrain surfaces. Your sources and observables can be placed anywhere in the scene. Your transmitters and receivers can be placed outdoors or indoors. A complete list of the various elements of a propagation scene is given in the '''Physical Structure''' section of [[Propagation Module]]'s Navigation Tree as follows:=== Scene Definition / Construction ===
* Impenetrable Surfaces<ul>* Penetrable Surfaces <li>* Buildings/blocks with arbitrary geometries and material properties</li> <li> Buildings/blocks with impenetrable surfaces or penetrable surfaces using thin wall approximation</li> <li> Multilayer walls for indoor propagation scenes</li> <li> Penetrable Volumesvolume blocks with arbitrary geometries and material properties</li>* <li> Import of shapefiles and STEP, IGES and STL CAD model files for scene construction</li> <li> Terrain Surfacessurfaces with arbitrary geometries and material properties and random rough surface profiles</li> <li> Import of digital elevation map (DEM) terrain models</li> <li> Python-based random city wizard with randomized building locations, extents and orientations</li> <li> Python-based wizards for generation of parameterized multi-story office buildings and several terrain scene types</li> <li> Standard half-wave dipole transmitters and receivers oriented along the principal axes</li> <li> Short Hertzian dipole sources with arbitrary orientation</li> <li> Isotropic receivers or receiver grids for wireless coverage modeling</li> <li> Radiator sets with 3D directional antenna patterns (imported from other modules or external files)</li> <li> Full three-axis rotation of imported antenna patterns</li> <li> Interchangeable radiator-based definition of transmitters and receivers (networks of transceivers)</li>* Base Points</ul>
Impenetrable, penetrable and terrain surfaces and penetrable volumes all obstruct the propagation of electromagnetic waves (rays) in the free space. What differentiates them is the types of physical phenomena that are used to model their interaction with the impinging rays. Base points are simply used to define transmitter and receiver locations in the scene. The following sections of this manual will describe each of these elements in detail.=== Wave Propagation Modeling ===
[[Image:PROP14<ul> <li> Fully 3D polarimetric and coherent Shoot-and-Bounce-Rays (1SBR).png|thumb|250px|The Navigation Tree simulation engine</li> <li> GTD/UTD diffraction models for diffraction from building edges and terrain</li> <li> Triangular surface mesh generator for discretization of EM.Terrano]].arbitrary block geometries</li> <li> Super-fast geometrical/optical ray tracing using advanced k-d tree algorithms</li> <li> Intelligent ray tracing with user defined angular extents and resolution</li> <li> Ray reflection, edge diffraction and ray transmission through multilayer walls and material volumes</li> <li> Communication link analysis for superheterodyne transmitters and receivers</li> <li> 17 digital modulation waveforms for the calculation of E<sub>b</sub>/N<sub>0</sub> and Bit error rate (BER)</li> <li> Incredibly fast frequency sweeps of the entire propagation scene in a single SBR simulation run</li> <li> Parametric sweeps of scene elements like building properties, or radiator heights and rotation angles</li> <li> Statistical analysis of the propagation scene</li> <li> Polarimetric channel characterization for MIMO analysis</li> <li> "Almost real-time" Polarimatrix solver using an existing ray database</li> <li> "Almost real-time" transmitter sweep using the Polarimatrix solver</li> <li> "Almost real-time" rotational sweep for modeling beam steering using the Polarimatrix solver</li> <li> "Almost real-time" mobile sweep for modeling mobile communications between Tx-Rx pairs along a mobile path using the Polarimatrix solver</li></ul>
=== The Various Types Of Surfaces Data Generation & Blocks Visualization ===
In a SBR simulation<ul> <li> Standard output parameters for received power, the propagating rays hit the surface of building structurespath loss, wallsSNR, terrain (or global ground) E<sub>b</sub>/N<sub>0</sub> and bounce back into BER at each individual receiver</li> <li> Graphical visualization of propagating rays in the scene </li> <li> Received power coverage maps</li> <li> Link connectivity maps (reflectionbased on minimum required SNR and BER). Some rays penetrate thin walls or other penetrable surfaces and continue their path on the other side </li> <li> Color-coded intensity plots of the surface (transmission). The polarimetric electric field intensitydistributions</li> <li> Incoming ray data analysis at each receiver including delay, phase angles of arrival and power departure</li> <li> Cartesian plots of path loss along defined paths</li> <li> Power delay profile of the reflected selected receiver</li> <li> Polar stem charts of angles of arrival and transmitted rays depend on the material properties departure of the obstructing surface. The specular surface can be modeled as a simple homogeneous dielectric half-space or as a multilayer structure. In that respect, the buildings, walls, terrain or even the global ground all behave in a similar way:selected receiver</li></ul>
* They terminate an impinging ray and replace it with one or more new rays.* They represent == Building a specular interface between two media of different material compositions for calculating the reflection, transmission and possibly diffraction coefficientsPropagation Scene in EM.Terrano ==
[[EM.Cube]] has generalized the concept of '''Block''' as any object that obstructs and affects radio wave propagation. Rays hit the facets === The Various Elements of a block and bounce off the surface of those facets or penetrate them and continue their propagation. Rays also get diffracted off the edges of these blocks. In [[EM.Cube]]'s [[Propagation Module]], blocks are grouped together by the type of their interaction with rays. [[EM.Cube]] currently offers three types of blocks for use in a propagation scene:Scene ===
# '''Impenetrable Surfaces:''' Rays hit the facets of this type of blocks and bounce back, but they do not penetrate the objectA typical propagation scene in EM. It is assumed that the interior Terrano consists of such blocks or buildings are highly absorptiveseveral elements.# '''Penetrable Surfaces:''' These blocks represent thin surfaces that are used At a minimum, you need a transmitter (Tx) at some location to model launch rays into the exterior scene and interior walls of buildings based on a receiver (Rx) at another location to receive and collect the "Thin Wall Approximation"incoming rays. Rays reflect off the surface of penetrable surfaces A transmitter and diffract off their edges. They also penetrate such thin surfaces and continue their paths on a receiver together make the other side simplest propagation scene, representing a free-space line-of the wall-sight (LOS) channel.# '''Terrain Surfaces:''' These blocks In EM.Terrano, a transmitter represents a point source, while a receiver represents a point observable. Both a transmitter and a receiver are used to provide one or more impenetrableassociated with point objects, ground surfaces for which are one of the propagation scene. Rays simply bounce off terrain many types of geometric objectsyou can draw in the project workspace. The global ground acts as Your scene might involve more than one transmitter and possibly a flat super-terrain that covers the bottom large grid of the entire computational domainreceivers.
[[EM.Cube]]'s [[Propagation Module]] allows you to define block groups A more complicated propagation scene usually contains several buildings, walls, or other kinds of each scatterers and wave obstructing objects. You model all of these elements by drawing geometric objects in the above three typesproject workspace or by importing external CAD models. EM. Each block group has Terrano does not organize the same color or texture and its members share the same geometric objects of your project workspace by their material properties: permittivity ε<sub>r</sub> and conductivity σcomposition. AlsoRather, all the penetrable surfaces belonging to the same block group have the same wall thickness. You can define many different block it groups with certain properties and underneath each introduce many member the geometric objects into blocks based on a common type of interaction with different geometrical shapes and dimensionsincident rays. The table below summarizes EM.Terrano offer the characteristics following types of each block typeobject blocks:
{| class="wikitable"
|-
! scope="col"| Icon! scope="col"| Block /Group Type! scope="col"|Physical EffectsRay Interaction Type! scope="col"|Admissible Object TypesAllowed! scope="col"| Notes
|-
| style="width:30px;" | [[File:impenet_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Impenetrable Surface| Impenetrable Surface]]| Reflectionstyle="width:200px;" | Ray reflection, Diffractionray diffraction| style="width:250px;" | All Solid solid &surface geometric objects, no curve objects| style="width:300px; Surface CAD Objects" | Basic building group for outdoor scenes
|-
| style="width:30px;" | [[File:penet_surf_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Penetrable Surface| Penetrable Surface]]| Reflectionstyle="width:200px;" | Ray reflection, Diffractionray diffraction, Transmissionray transmission in free space| style="width:250px;" | All Solid solid &surface geometric objects, no curve objects| style="width:300px; Surface CAD Objects" | Behaves similar to impenetrable surface and uses thin wall approximation for generating transmitted rays, used to model hollow buildings with ray penetration, entry and exit
|-
| style="width:30px;" | [[File:terrain_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Terrain Surface| Terrain Surface]]| Reflectionstyle="width:200px;" | Ray reflection, ray diffraction| Tessellated Objects style="width:250px;" | All surface geometric objects, no solid or curve objects | style="width:300px;" | Behaves exactly like impenetrable surface but can change the elevation of all the buildings and transmitters and receivers located above it|-| style="width:30px;" | [[File:penet_vol_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Penetrable Volume | Penetrable Volume]]| style="width:200px;" | Ray reflection, ray diffraction, ray transmission and ray attenuation inside homogeneous material media| style="width:250px;" | All solid geometric objects, no surface or curve objects| style="width:300px;" | Used to model wave propagation inside a volumetric material block, also used for creating individual solid walls and interior building partitions and panels in indoor scenes|-| style="width:30px;" | [[File:base_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Base Location Set | Base Location Set]]| style="width:200px;" | Either ray generation or ray reception| style="width:250px;" | Onlypoint objects| style="width:300px;" | Required for the definition of transmitters and receivers|-| style="width:30px;" | [[File:scatterer_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Point Scatterer Set | Point Scatterer Set]]| style="width:200px;" | Ray reception and ray scattering| style="width:250px;" | Only point, box and sphere objects| style="width:300px;" | Required for the definition of point scatterers as targets in a radar simulation |-| style="width:30px;" | [[File:Virt_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Virtual_Object_Group | Virtual Object]]| style="width:200px;" | No ray interaction| style="width:250px;" | All types of objects| style="width:300px;" | Used for representing non-physical items
|}
=== Impenetrable Surfaces For Outdoor Scenes ===Click on each type to learn more about it in the [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types]].
[[File:PROP14Impenetrable surfaces, penetrable surfaces, terrain surfaces and penetrable volumes represent all the objects that obstruct the propagation of electromagnetic waves (2rays)in the free space.png|thumb|200px|[[Propagation Module]]'s Impenetrable Surface dialog]] What differentiates them is the types of physical phenomena that are used to model their interaction with the impinging rays. EM.Terrano discretizes geometric objects into a number of flat facets. The field intensity, phase and power of the reflected and transmitted rays depend on the material properties of the obstructing facet. The specular surface of a facet can be modeled locally as a simple homogeneous dielectric half-space or as a multilayer medium. In that respect, all the obstructing objects such as buildings, walls, terrain, etc. behave in a similar way:
In outdoor propagation scenes such as "Urban Canyons", you are primarily interested in the wireless coverage in the areas among buildings. You can assume that rays bounce off the exterior walls of these buildings but do not penetrate them. In other words, you ignore the transmitted rays * They terminate an impinging ray and assume that they are either absorbed replace it with one or diffused inside the buildingsmore new rays. This is not an unrealistic assumption. [[EM.Cube]] offers "Impenetrable Blocks" to model buildings in outdoor propagation scenes. A penetrable block has * They represent a color or texture property as well as specular interface between two media of different material properties: permittivity (e<sub>r</sub>) and conductivity (s). By defaultcompositions for calculating the reflection, a brick building is assumed with ε<sub>r</sub> = 4.4 and σ = 0.001 S/m. Impinging rays are reflected from the facets of impenetrable buildings transmission or diffracted from their edgesdiffraction coefficients.
To define An outdoor propagation scene typically involves several buildings modeled by impenetrable surfaces. Rays hit the facets of impenetrable buildings and bounce back, but they do not penetrate the object. It is assumed that the interior of such buildings are highly dissipative due to wave absorption or diffusion. An indoor propagation scene typically involves several walls, a new ceiling and a floor arranged according to a certain building layout. Penetrable surfaces are used to model the exterior and interior walls of buildings. Rays reflect off these surfaces and diffract off their edges. They also penetrate the thin surface and continue their path in the free space on the other side of the wall. Terrain surfaces with irregular shapes or possibly random rough surfaces are used as an alternative to the flat global ground. You can also build mixed scenes involving both impenetrable and penetrable blocks or irregular terrain. In the context of a propagation scene, penetrable volumes are often used to model block groupof rain, follow these steps:fog or vegetation. Base location sets are used to geometrically represent point transmitters and point receivers in the project workspace.
# Right click on either Sometimes it is helpful to draw graphical objects as visual clues in the '''Impenetrable Surfaces''' item of the Navigation Tree and select '''Insert New Blockproject workspace...''' A dialog for setting up the block properties opens up offering These non-physical objects must belong to a preloaded material type (Brick) with predefined color and texture.# Specify a name for the block virtual object group and select a color or texture.# The electromagnetic model that determines ray-block interaction is selected under '''Specular Interface Type'''Virtual objects are not discretized by EM. Two options are available: Terrano'''Standard Material''' or '''User Defined Model'''. The former is the default choice and requires material propertiess mesh generator, '''Permittivity''' (ε<sub>r</sub>) and '''Electric Conductivity''' (σ), which they are set to "Brick" by default. No magnetic properties are allowed for blocks.# Click not passed onto the '''OK''' button input data files of the dialog to accept the changes and close itSBR simulation engine.
Under an impenetrable block group, you can draw any of <table><tr><td> [[Image:PROP MAN2.png|thumb|left|720px|An urban propagation scene generated by EM.Cube]]Terrano's native solid or [[Surface Objects|surface objects]] or you can import external model files like STEP, IGES or STL. You can change the properties of an impenetrable surface"Random City" and "Basic Link" wizards. In the property dialog It consists of the surface group25 cubic brick buildings, click on the table that list the properties to select one transmitter and highlight a row. Then, click the '''Add/Edit''' button to open up the "Edit Layer" dialog. In this dialog, you can change the name large two-dimensional array of the material and its permittivity and electric conductivityreceivers. The box labeled "Specify Loss Tangent" is unchecked by default. If you check it, you can specify the '''Loss Tangent''' of the material, which, in turn, updates the value of electric conductivity at the center frequency of the project. You can also use [[EM.Cube]]'s Material List, which will be explained later. </td></tr></table>
[[File:PROP23.png]]=== Organizing the Propagation Scene by Block Groups ===
Figure: [[Propagation Module]]'s "Edit Layer" dialog corresponding to impenetrable In EM.Terrano, all the geometric objects associated with the various scene elements like buildings, terrain surfacesand base location points are grouped together as blocks based on their common type. All the objects listed under a particular group in the navigation tree share the same color, texture and material properties. Once a new block group has been created in the navigation tree, it becomes the "Active" group of the project workspace, which is always displayed in bold letters. You can draw new objects under the active node. Any block group can be made active by right-clicking on its name in the navigation tree and selecting the '''Activate''' item of the contextual menu.
=== Penetrable Surfaces For Indoor Scenes ===<table><tr><td> [[Image:PROP MAN1.png|thumb|left|480px|EM.Terrano's navigation tree.]]</td></tr></table>
[[File:PROP15(1)It is recommended that you first create block groups, and then draw new objects under the active block group.png|thumb|200px|[[Propagation Module]]'s Penetrable Surface However, if you start a new EM.Terrano project from scratch, and start drawing a new object without having previously defined any block groups, a new default impenetrable surface group is created and added to the navigation tree to hold your new CAD object. You can always change the properties of a block group later by accessing its property dialog]]from the contextual menu. You can also delete a block group with all of its objects at any time.
A typical indoor propagation scene usually involves an arrangement of walls that represent the interior of a building. The transmitters and receivers are then placed in the spaces among such walls. From the point of view of [[EM.Cube]]'s SBR simulator{{Note|You can only import external CAD models (STEP, IGES, walls act like thin penetrable surfacesSTL, DEM, etc. [[EM.Cube]] uses the "Thin Wall Approximation" ) only to model penetrable surfaces. It assumes that rays simply penetrate a wall and exit at the same specular point on the opposite side of the wallCubeCAD module. In other words, rays are not displaced by You can then transfer the walls, nor do they get trapped inside the walls (no internal reflection). This is equivalent imported objects from CubeCAD to assuming a zero thickness for penetrable surfaces for the purpose of geometrical ray tracing, while the finite thickness of the "thin" surface is used for electromagnetic calculation of transmission coefficient. [[EM.Cube]] offers "Penetrable Surface Blocks" for the construction of rooms in indoor propagation scenes as well as modeling of hollow buildings and other structures. You can define many penetrable surface groups with arbitrary thicknesses and material properties (color, texture, permittivity and electric conductivity)Terrano.}}
To define a new penetrable surface group, follow these steps:=== Moving Objects Among Different Block Groups ===
# Right click on You can move any geometric object or a selection of objects from one of the block group to another. You can also transfer objects among [[EM.Cube]]'''Penetrable Surfaces''' item in the Navigation Tree and select '''Insert New Blocks different modules.For example, you often need to move imported CAD models of terrain or buildings from CubeCAD to EM.Terrano.''' A dialog for setting up To transfer objects, first select them in the wall properties opens up offering a preloaded material type (Brick) with predefined color and textureproject workspace or select their names in the navigation tree.# Specify a name for the surface group Then right-click on them and select a color or texture<b>Move To → Module Name → Object Group</b> from the contextual menu.# The properties of For example, if you want to move a penetrable surface are identical selected object to those of an impenetrable surface, plus an additional thickness propertya block group called "Terrain_1" in EM.# By defaultTerrano, a brick wall with a thickness of 0.5 units is assumed. You can change then you have to select the menu item '''Thickness''' of the penetrable surface as well as its '''Permittivity''' Move To &epsilonrarr;<sub>r</sub> and EM.Terrano → Terrain_1'''Electric Conductivity''' σas shown in the figure below.# Click Note that you can transfer several objects altogether using the keyboards'''OK''' button of the dialog s {{key|Ctrl}} or {{key|Shift}} keys to accept the changes and close itmake multiple selections.
Under a penetrable surface group, you can draw any of <table><tr><td> [[Image:PROP MAN3.png|thumb|left|720px|Moving the terrain model of Mount Whitney originally imported from an external digital elevation map (DEM) file to EM.CubeTerrano.]]'s native solid or </td></tr><tr><td>[[Surface ObjectsImage:PROP MAN4.png|thumb|left|720px|surface objects]] or you can import external The imported terrain model files like STEP, IGES or STL. You can change the properties of a penetrable surface group including its default thicknessMount Whitney shown in EM. In the property dialog of the surface group, click on the table that list the properties to select and highlight a row. Then, click the Terrano'''Add/Edit''' button to open up the "Edit Layer" dialog. Similar to the case of impenetrable surfaces, from this dialog, you can change the material properties (permittivity and electric conductivity) as well as '''Thickness''', which is expressed in the s project units. You can also use [[EMworkspace under a terrain group called "Terrain_1".Cube]]'s Material List, which will be explained later.</td></tr></table>
[[File:PROP25.png]]=== Adjustment of Block Elevation on Underlying Terrain Surfaces ===
Figure 2: [[Propagation Module]]'s "Edit Layer" In EM.Terrano, buildings and all other geometric objects are initially drawn on the XY plane. In other words, the Z-coordinates of the local coordinate system (LCS) of all blocks are set to zero until you change them. Since the global ground is located a z = 0, your buildings are seated on the ground. When your propagation scene has an irregular terrain, you would want to place your buildings on the surface of the terrain and not buried under it. This can be done automatically as part of the definition of the block group. Open the property dialog corresponding of a block group and check the box labeled '''Adjust Block to Terrain Elevation'''. All the objects belonging to penetrable surfacesthat block are automatically elevated in the Z direction such that their bases sit on the surface of their underlying terrain. In effect, the LCS of each of these individual objects is translated along the global Z-axis by the amount of the Z-elevation of the terrain object at the location of the LCS.
{{Note| You can construct several thin walls have to make sure that the resolution of your terrain, its variation scale and arrange them as roomsbuilding dimensions are all comparable. A regular room can be built by placing four vertical wall objects together with an optional horizontal wall at the top for the ceiling. AlternativelyOtherwise, on a rapidly varying high-resolution terrain, you may use [[EM.Cube]]'s hollow box objects or boxes with one or two capped end(s). '''Keep in mind that all the penetrable surfaces belonging to a group will have buildings whose bottoms touch the same wall thickness, which is initially set to 0.5 project units by default. Also, note that solid CAD objects belonging to terrain only at a penetrable surface group are treated as air-filled hollow structures.''' The thickness few points and parts of penetrable surfaces is implied and not visualized when displaying objects them hang in the project workspaceair.}}
=== Computational Domain & Global Ground ===<table><tr><td> [[Image:PROP MAN5.png|thumb|left|480px|The property dialog of impenetrable surface showing the terrain elevation adjustment box checked.]]</td></tr></table>
The SBR simulation engine requires a finite computational domain<table><tr><td> [[Image:PROP MAN6. All the stray rays that hit the boundaries png|thumb|left|360px|A set of this finite domain are terminated during the simulation process. Such rays exit the computational domain and travel to the infinity, with no chance of ever reaching any receiver in the scene. When you define a propagation scene with various elements like buildings, walls, on an undulating terrain, etcwithout elevation adjustment., a dynamic domain is automatically established and displayed as a wireframe box with green lines that surrounds the entire scene]]</td><td>[[Image:PROP MAN7. Every time you create a new object, png|thumb|left|360px|The set of buildings on the domain is automatically adjusted and extended to enclose all the objects in the sceneundulating terrain after elevation adjustment. You can change the size and color of the domain box through the Ray Domain Settings Dialog, which can be accessed in one of the following three ways:]]</td></tr></table>
# Click the '''Domain''' [[File:image025== EM.jpg]] button of the Simulation Toolbar.# Select the Terrano'''Simulate''' > '''Computational s Ray Domain''' > '''Settings...''' item of the Simulate Menu.# Right click on the '''Ray Domain''' item of the Navigation Tree and select '''Domain Settings...'''# Use the keyboard shortcut '''Ctrl + A'''.Global Environment ==
The size of the Ray domain is specified in terms of six '''Offset''' [[parameters]] along the ±X, ±Y and ±Z directions. The default value of all these six offset [[parameters]] is 10 project units. === Why Do You can change them arbitrarily. After changing these values, use the '''Apply''' button to make the changes effective while the dialog is still open.Need a Finite Computational Domain? ===
[[File:PROP15The SBR simulation engine requires a finite computational domain for ray termination. All the stray rays that emanate from a source inside this finite domain and hit its boundaries are terminated during the simulation process. Such rays exit the computational domain and travel to the infinity, with no chance of ever reaching any receiver in the scene. When you define a propagation scene with various elements like buildings, walls, terrain, etc., a dynamic domain is automatically established and displayed as a green wireframe box that surrounds the entire scene. Every time you create a new object, the domain box is automatically adjusted and extended to enclose all the objects in the scene.png]]
Figure 1To change the ray domain settings, follow the procedure below: [[Propagation Module]]'s Domain Settings dialog.
Most outdoor and indoor propagation scenes include a flat ground at their bottom, which bounces incident rays back into * Open the scene. Ray Domain Settings Dialog by clicking the '''Domain''' [[EMFile:image025.Cubejpg]]'s [[Propagation Module]] provides a global flat ground at z = 0. The global ground indeed acts as an impenetrable surface that blocks the entire computational domain from the z = 0 plane downward. It is displayed as a translucent green plane at z = 0 extending downward. The color button of the ground plane is always the same as the color of the ray domain. The global ground is assumed to be made of a homogeneous dielectric material with a specified permittivity ε<sub'''Simulate Toolbar''', or by selecting '''Menu >r</subSimulate > and electric conductivity σ. By default, a rocky ground is assumed with ε<subComputational Domain >r</sub> = 5 and σ = 0Settings.005 S/m. You can remove the global ground, in which case, you will have a free space scene. To disable the global ground''', open up the Global Ground Settings Dialog, which can be accessed or by right -clicking on the '''Global GroundRay Domain''' item in of the Navigation Tree navigation tree and selecting '''Global Ground Domain Settings... '''Remove the check mark from the box labeled contextual menu, or simply using the keyboard shortcut {{key|Ctrl+A}}.* The size of the Ray domain is specified in terms of six '''"Include Half-Space Ground (z<0)"Offset''' to disable parameters along the global ground±X, ±Y and ±Z directions. This will also remove the green translucent plane from the bottom The default value of your sceneall these six offset parameters is 10 project units. Change these values as you like.* You can also change the material properties color of the global ground and set new values for domain box using the permittivity and electric conductivity of {{key|Color}} button.* After changing the impenetrablesettings, half-space, dielectric medium. '''Do not forget use the {{key|Apply}} button to disable make the global ground if you want to model a free space propagation scenechanges effective while the dialog is still open.'''
<table><tr><td> [[FileImage:PROP4PROP15.png|thumb|left|480px|EM.Terrano's domain settings dialog.]]</td></tr></table>
Figure 2: [[Propagation Module]]'s === Understanding the Global Ground Settings dialog.===
Most outdoor and indoor propagation scenes include a flat ground at their bottom, which bounces incident rays back into the scene. EM.Terrano provides a global flat ground at z =0. The global ground indeed acts as an impenetrable surface that blocks the entire computational domain from the z =0 plane downward. It is displayed as a translucent green plane at z = Terrain Surfaces vs0 extending downward. Global Ground =The color of the ground plane is always the same as the color of the ray domain. The global ground is assumed to be made of a homogeneous dielectric material with a specified permittivity ε<sub>r</sub> and electric conductivity σ. By default, a rocky ground is assumed with ε<sub>r</sub> =5 and σ =0.005 S/m. You can remove the global ground, in which case, you will have a free space scene. To disable the global ground, open up the "Global Ground Settings" dialog, which can be accessed by right clicking on the '''Global Ground''' item in the Navigation Tree and selecting '''Global Ground Settings... '''Remove the check mark from the box labeled '''"Include Half-Space Ground (z<0)"''' to disable the global ground. This will also remove the green translucent plane from the bottom of your scene. You can also change the material properties of the global ground and set new values for the permittivity and electric conductivity of the impenetrable, half-space, dielectric medium.
[[File:PROP16Alternatively, you can use EM.png|thumb|200px|[[Propagation Module]]Terrano's Terrain dialog]]'''Empirical Soil Model''' to define the material properties of the global ground. This model requires a number of parameters: Temperature in °C, and Volumetric Water Content, Sand Content and Clay Content all as percentage.
A terrain surface acts as {{Note|To model a custom, unlevel or irregular ground for your free-space propagation scene. [[, you have to disable EM.Cube]]Terrano's default global ground blocks the z < 0 half-space everywhere in the computational domain. You can simply turn off the global ground and create one or more terrain objects and place them arbitrarily in the scene. You can also import an external terrain model or file. A terrain represents an impenetrable surface with a more complex surface profile. You can have one or more terrain objects of finite extents and place them on or above the global ground.}}
Terrain objects have some important differences with objects of the "Impenetrable Surface" type<table><tr><td> [[Image:Global environ.png|thumb|left|720px|EM.Terrano's Global Environment Settings dialog.]]</td></tr></table>
# While impenetrable blocks can be created using any of [[EM.Cube]]'s solid or surface CAD object creation tools, terrain objects are created either using [[EM.Cube]]'s '''Terrain Generator''' or by importing an external terrain file. # Terrain objects belong to a special type of CAD objects called == Defining Point Transmitters "amp;Tessellated Objects", which differ from other regular CAD [[Surface Objects|surface objects]] or [[EM.Cube]]'s polymesh surfaces.# Terrain surfaces do not diffract impinging rays at their many small edges.# Terrain objects affect the elevation of other objects or transmitters or receivers that are located above them.Point Receivers for Your Propagation Scene ==
Just as other blocks are grouped by their color, texture and material composition, terrain objects are also grouped in a similar fashion. Before you can generate or import a new terrain object, first you have to define a terrain group and specify its color/texture and material properties. To define a new terrain group, follow these steps:=== The Nature of Transmitters & Receivers ===
* Right click on In EM.Terrano, transmitters and receivers are indeed point radiators used for transmitting and receiving signals at different locations of the '''Terrain''' item propagation scene. From a geometric point of view, both transmitters and receivers are represented by point objects or point arrays. These are grouped as base locations in the Navigation Tree "Physical Structure" section of the navigation tree. As radiators, transmitters and select '''Insert New Terrain.receivers are defined by a radiator type with a certain far-field radiation pattern.Consistent with [[EM.Cube]]''' A dialog for setting up the terrain properties opens up offering s other computational modules, transmitters are categorizes as an excitation source, while receivers are categorized as a of preloaded material type (Rock) with predefined green color and no textureproject observable.* Specify In other words, a name for transmitter is used to generate electromagnetic waves that propagate in the terrain group and select a color or texturephysical scene.* Similar to A receiver, on the other blockshand, you have is used to specify compute the material properties, Permittivity (ε<sub>r</sub>) received fields and Electric Conductivity received signal power or signal-to-noise ratio (σSNR). For this reason, of the terrain group. Rock with ε<sub>r</sub> = 5 transmitters are defined and σ = 0.005 S/m is listed under the default material choice for a new terrain.* Click the '''OK''' button "Sources" sections of the dialog to accept navigation tree, while receivers are defined and listed under the changes and close it"Observables" section.
You can change the properties of a terrain surface group from its property dialog. Click on the table that list the properties to select and highlight a row. Then, click the '''Add/Edit''' button to open up the "Edit Layer" dialog, which is identical to the case of impenetrable surfaces. You can also use [[EM.Cube]]'s Material List, which will be explained later. When a new terrain type is created, its node on the Navigation Tree becomes active. Under this node you can create and add new terrain objects. When a terrain node is active for drawing, all CAD object creation tools are disabled. You have Terrano provides three options radiator types for creating a new terrain object, which will be described in detail in the next sections of this manualpoint transmitter sets:
# Use [[EM.Cube]]'s '''Terrain Generator'''.Half-wave dipole oriented along one of the three principal axes# Import an external terrain file of "'''.TRN'''" type.Two collocated, orthogonally polarized, isotropic radiators # Import an external terrain file of "'''.DEM'''" type.User defined (arbitrary) antenna with imported far-field radiation pattern
Click here to learn more about [[Using Terrain Generator]]EM.Terrano also provides three radiator types for point receiver sets:
[[File:PROP18.png|thumb|250px|[[Propagation Module]]'s Terrain Generator dialog]]#Half-wave dipole oriented along one of the three principal axes#Polarization-matched isotropic radiator#User defined (arbitrary) antenna with imported far-field radiation pattern
=== Importing & Exporting Terrain Models ===The default transmitter and receiver radiator types are both vertical (Z-directed) half-wave dipoles.
You can import two types of terrain in [[EM.Cube]]'s [[Propagation Module]]. The first type is "'''.TRN"''' terrain file, which is [[EM.Cube]]'s native terrain format. It is There are three different ways to define a basic digital elevation map with a very simple ASCII data file format. The resolution of the terrain map in the X and Y directions is specified in meters as STEPS. The (x, y, z) coordinates of the terrain points are then listed one point per line. The other type of terrain format supported by [[EM.Cube]] is the standard '''7.5min DEM''' file format with transmitter set or a '''.DEM''' file extension. receiver set:
To import an external terrain model, first you have to create a terrain group node *By defining point objects or point arrays under physical base location sets in the Navigation Tree. Right click on the name of the terrain group in the Navigation Tree navigation tree and select either '''Import Terrain...''' then associating them with a transmitter or '''Import DEM File...''' A standard [[Windows]] '''Open Dialog''' opens upreceiver set*Using Python commands emag_tx, with the file type set to .TRN or .DEM extensionsemag_rx, emag_tx_array, emag_rx_array, respectively. You can browse your folders emag_tx_line and find emag_rx_line*Using the right terrain model file to import."Basic Link" wizard
You can also export all the terrain objects in the project workspace as === Defining a terrain file with a '''.TRN''' file extension. You can even import a DEM terrain model from an external file and then save and export it as a native terrain (.TRN) file. To export the terrain, select '''File''' > '''Export...''' from [[Propagation Module]]'s '''File Menu'''. The standard [[Windows]] Save Dialog opens up with the default file type set to '''.TRN'''. Type Point Transmitter Set in a name for your new terrain file and click the '''Save''' button to export the terrain data.Formal Way ===
[[File:prop_manual-12_tnTransmitters act as sources in a propagation scene.png|800px]]A transmitter is a point radiator with a fully polarimetric radiation pattern defined over the entire 3D space in the standard spherical coordinate system. EM.Terrano gives you three options for the radiator associated with a point transmitter:
Figur: An imported external terrain model.* Half-wave dipole* Orthogonally polarized isotropic radiators* User defined antenna pattern
=== Multilayer Surface Models ===By default, EM.Terrano assumes that your transmitter is a vertically polarized (Z-directed) resonant half-wave dipole antenna. This antenna has an almost omni-directional radiation pattern in all azimuth directions. It also has radiation nulls along the axis of the dipole. You can change the direction of the dipole and orient it along the X or Y axes using the provided drop-down list. The second choice of two orthogonally polarized isotropic radiators is an abstract source that is used for polarimetric channel characterization as will be discussed later.
You can override the default radiator option and select any other kind of antenna with a more complicated radiation pattern. For this purpose, you have to import a radiation pattern data file to EM.Terrano. You can model any radiating structure using [[File:PROP26EM.png|thumb|200px|Propagation ModuleCube]]'s Penetrable Surface Dialog showing a three-layer wall compositionother computational modules, [[EM.Tempo]], [[EM.Picasso]], [[EM.Libera]] or [[EM.Illumina]], and generate a 3D radiation pattern data file for it. The far-field radiation patter data are stored in a specially formatted file with a "'''.RAD'''" file extension. This file contains columns of spherical φ and θ angles as well as the real and imaginary parts of the complex-valued far-zone electric field components '''E<sub>θ</sub>''' and '''E<sub>φ</sub>'''. The θ- and φ-components of the far-zone electric field determine the polarization of the transmitting radiator.
Most of the time{{Note|By default, your outdoor propagation scene consists of simple buildings made of single-layer walls with standard material properties (ε<sub>r</sub> and σ)EM. In the case of Terrano assumes a single-layer impenetrable surface, the specular interface is an infinite dielectric vertical half-space, which reflects the impinging rays. Single-layer penetrable surfaces, on the other hand, involve finite-thickness dielectric walls, which both reflect and transmit the incident rays. Similarly, most of wave dipole radiator for your indoor propagation scenes involve simple single-layer penetrable walls with the specified material properties ε<sub>r</sub> and σ. A thin wall acts like a finite-thickness dielectric slab that both reflects and transmits incident rays. In the case of the global ground or terrain objects, only ray reflection off the ground surface is consideredpoint transmitter set.}}
In [[EM.Cube]]'s [[Propagation Module]], you can define multilayer surfaces A transmitter set always needs to be associated with both reflection and transmission properties. You can define multilayer impenetrable buildings, multilayer penetrable walls, and multilayer terrain, an existing base location set with an arbitrary number of layers having different material compositions. You define a multilayer surface one or more point objects in the property dialog of a block, whether impenetrable, penetrable or terrainproject workspace. In the section entitled '''Surface Type'''Therefore, two options are available: '''Standard Material''' or '''User Defined Model'''. For simple multilayer walls, select the '''Standard Material''' option. You can add new layers with arbitrary thickness and material [[parameters]] to the existing layers. To insert a new layer, deselect any items in the layer list, and click the '''Add/Edit''' button to open the "Add Layer" Dialog. Here you can enter cannot define a name transmitter for the new layer and values for its '''Thickness''', ε<sub>r</sub> and σ. You may also delete any layer by selecting and highlighting it and clicking the '''Delete''' button. You can move layers up or down using the '''Move Up''' and '''Move Down''' buttons and change the layer hierarchyyour scene before drawing a point object under a base location set.
You can also search [[EMImage:Info_icon.Cubepng|40px]]Click here to learn how to define a 's material database by clicking the '''Material''' button of "Add Layer" or "Edit Layer" dialogs[[Glossary_of_EM. This opens the Cube%27s_Materials,_Sources,_Devices_%26_Other_Physical_Object_Types#Point_Transmitter_Set | Point Transmitter Set]]'''Materials''' Dialog. Inside the material list select and highlight any row and click the '''OK''' button. The selected material will fill out all the fields in the "Add Layer" or "Edit Layer" dialogs. Inside the Materials Dialog, you can type the few first letters of any material, and it will take you to the corresponding row of the list.
<table><tr><td> [[FileImage:PROP24Terrano L1 Fig11.png|thumb|left|480px|The point transmitter set definition dialog.]]</td></tr></table>
Figure: Once you define a new transmitter set, its name is added in the '''Transmitters''' section of the navigation tree. The color of all the base points associated with the newly defined transmitter set changes, and an additional little ball with the transmitter color (red by default) appears at the location of each associated base point. You can open the property dialog of the transmitter set and modify a number of parameters including the '''Source Power''' in Watts and the broadcast signal '''Phase''' in degrees. The default transmitter power level is 1W or 30dBm. There is also a check box labeled '''Use Custom Input Power''', which is checked by default. In that case, the power and phase boxes are enabled and you can change the default 1W power and 0° phase values as you wish. [[EM.Cube]]'s material list".RAD" radiation pattern files usually contain the value of "Total Radiated Power" in their file header. This quantity is calculated based on the particular excitation mechanism that was used to generate the pattern file in the original [[EM.Cube]] module. When the "Use Custom Input Power" check box is unchecked, EM.Terrano will use the total radiated power value of the radiation file for the SBR simulation.
=== Transferring Objects From Or To Other Modules ==={{Note|In order to modify any of the transmitter set's parameters, first you need to select the "User Defined Antenna" option, even if you want to keep the vertical half-wave dipole as your radiator.}}
When you start a new project in <table><tr><td> [[EMFile:NewTxProp.png|thumb|left|720px|The property dialog of a point transmitter set.Cube]]'s [[Propagation Module]] and draw a solid object like a box in the project workspace without having defined any surface groups, it is assumed to be of the impenetrable surface type. A default impenetrable surface group called Block_1 is automatically added to the Navigation Tree, which holds your newly drawn object. The default group has the material properties of "Brick" (ε<sub/td>r</subtr> = 4.4 and σ = 0.001 S</m.) with a dark brown color. You can continue drawing new objects in the project workspace and adding them under this block node. Or you can define a new surface type with different properties. By default, the last surface group that was defined is '''Active'''. The current active surface group is always listed in bold letters in the Navigation Tree. When you draw a new object, it is always inserted under the current active surface group. Any surface group can be activated by right clicking its name in the Navigation Tree and selecting the '''Activate''' item of the contextual menu.table>
You can move any object from its current surface group into any other available surface groupYour transmitter in EM. First select the objectTeranno is indeed more sophisticated than a simple radiator. It consists of a basic "Transmitter Chain" that contains a voltage source with a series source resistance, then right click on its surface and select '''MoveTo > Propagation >'''. A submenu appears connected via a segment of transmission line to a transmit antenna, which lists all is used to launch the broadcast signal into the available surface groups where free space. The transmitter's property dialog allows you can transfer to define the selected objectbasic transmitter chain. You can also move objects among surface groups by selecting their names in Click the Navigation Tree and using {{key|Transmitter Chain}} button of the contextual menu. In a similar way, you can transfer objects from [[Propagation Module]] Transmitter Set dialog to [[EMopen the transmitter chain dialog.Cube]]'s other modules or vice versa. '''Keep As shown in mind that all the external model files such as STEPfigure below, IGES, STL, etc. are first imported to [[EM.Cube]]'s [[CubeCAD]], from which you can transfer them to other modules.''' First select specify the characteristics of the objectbaseband/IF amplifier, then right click mixer and select '''MoveTo >'''power amplifier (PA) including stage gains and impedance mismatch factors (IMF) as well as the characteristics of the transmission line segment that connects the PA to the antenna. In Note that the submenu you will see a list transmit antenna characteristics are automatically filled using the contents of all the [[EMimported radiation pattern data file.Cube]] modules that have at least one available group where you can transfer The transmitter Chain dialog also calculates and reports the "Total Transmitter Chain Gain" based on your selected object. You can select multiple objects for transferinput. When using you close this dialog and return to the keyboard's '''Shift Key''' or '''Ctrl Key''' for multiple selection, make sure that those keys are held downTransmitter Set dialog, when you right click to access will see the contextual menucalculated value of the Effective Isotropic Radiated Power (EIRP) of your transmitter in dBm.
== Defining Sources {{Note| If you do not modify the default parameters of the transmitter chain, a 50-&Omega; Observables ==conjugate match condition is assumed and the power delivered to the antenna will be -3dB lower than your specified baseband power.}} <table><tr><td> [[File:NewTxChain.png|thumb|left|720px|EM.Terrano's point transmitter chain dialog.]] </td></tr></table>
Like every other electromagnetic solver, [[EM.Cube]]'s SBR ray tracer requires === Defining a source for excitation and one or more observables for generation of simulation data. [[EM.Cube]]'s new [[Propagation Module]] offers several types of sources and observables for a SBR simulation. You can mix and match different source types and observable types depending on Point Receiver Set in the requirements of your modeling problem. There are two types of sources:Formal Way ===
* [[#Defining Transmitter Sets|Transmitter]]* [[#Hertzian Dipole Sources|Hertzian Dipole]]Receivers act as observables in a propagation scene. The objective of a SBR simulation is to calculate the far-zone electric fields and the total received power at the location of a receiver. You need to define at least one receiver in the scene before you can run a SBR simulation. Similar to a transmitter, a receiver is a point radiator, too. EM.Terrano gives you three options for the radiator associated with a point receiver set:
There are four types of observables:* Half-wave dipole* Polarization matched isotropic radiator* User defined antenna pattern
* [[#Defining Receiver Sets|Receivers]]* [[#Defining Field Sensors|Field Sensor]]* Far Fields* Huygens SurfaceBy default, EM.Terrano assumes that your receiver is a vertically polarized (Z-directed) resonant half-wave dipole antenna. You can change the direction of the dipole and orient it along the X or Y axes using the provided drop-down list. An isotropic radiator has a perfect omni-directional radiation pattern in all azimuth and elevation directions. An isotropic radiator doesn't exist physically in the real world, but it can be used simply as a point in space to compute the electric field.
The simplest SBR simulation can be performed using You may also define a short dipole source with a specified field sensor planecomplicated radiation pattern for your receiver set. In this waythat case, [[EM.Cube]] computes the electric and magnetic fields radiated by your dipole source in the presence of your multipath propagation environment. A "classic" urban propagation scene can be set up using a "Transmitter" source and an array of "Receiver" observables. A transmitter is a point radiator with you need to import a user defined radiation patterndata file to EM. A receiver is a polarization-matched isotropic point radiator that collects Terrano similar to the received rays at its aperture. Using receivers, you can calculate the received power coverage map case of your propagation scene. You can also calculate your channel's path loss between the a transmitter and all the receiversset. <br />
=== Hertzian Dipole Sources ==={{Note|By default, EM.Terrano assumes a vertical half-wave dipole radiator for your point receiver set.}}
[[File:PROP18(1).png|thumb|[[Propagation Module]]'s Transmitter dialog Similar to transmitter sets, you define a receiver set by associating it with a short dipole radiator selected]]Earlier versions of [[EM.Cube]]'s [[Propagation Module]] used to offer an isotropic radiator existing base location set with vertical one or horizontal polarization as more point objects in the simplest transmitter typeproject workspace. This release of [[EM.Cube]] has abandoned isotropic radiator transmitters because they do not exist physically in a real world. Instead, All the default transmitter receivers belonging to the same receiver set have the same radiator type is now . A typical propagation scene contains one or few transmitters but usually a Hertzian dipolelarge number of receivers. Note that before defining To generate a transmitterwireless coverage map, first you have need to define a an array of points as your base set to establish the location of the transmitter. Most simulation scenes involve only a single transmitter. Your base set can be made up of a single point for this purpose.
To [[Image:Info_icon.png|40px]] Click here to learn how to define a new Transmitter Set, go to the '''Sources''' section of the Navigation Tree, right click on the '''Transmitters''' item and select '''Insert Transmitter[[Glossary_of_EM...''' A dialog opens up that contains a default name for the new Transmitter Cube%27s_Simulation_Observables_%26_Graph_Types#Point_Receiver_Set | Point Receiver Set as well as a dropdown list labeled ]]'''Select Base Set'''. In this list you will see all the available base sets already defined in the project workspace. Select the desired base set to associate with the transmitter set. Note that if the base set contains more than one point, then more than one transmitter will be created and contained in your transmitter set. After defining a transmitter set, the base points change their color to the transmitter color, which is red by default.
In the "Radiator" section of the dialog, you have two options to choose from<table><tr><td> [[Image: "Short Dipole" and "User Defined"Terrano L1 Fig12. png|thumb|left|480px|The default option is short dipolepoint receiver set definition dialog. A short dipole radiator has a '''Length'''''dl'' expressed in project units, a current '''Amplitude''' in Amperes and a current '''Phase''' in degrees. The '''Direction''' of the dipole is determined by its unit vector that has three X, Y and Z components. By default, a Z-directed short dipole radiator is assumed. You can change all [[parameters]] of the dipole as you wish. Keep in mind that all the transmitters belonging to the same set have parallel radiators with identical properties.</td></tr></table>
=== Defining Base Point Sets ===Once you define a new receiver set, its name is added to the '''Receivers''' section of the navigation tree. The color of all the base points associated with the newly defined receiver set changes, and an additional little ball with the receiver color (yellow by default) appears at the location of each associated base point. You can open the property dialog of the receiver set and modify a number of parameters.
<table><tr><td> [[File:PROP1NewRxProp.png|thumb|[[Propagation Module]]'s Base Set left|720px|The property dialogof a point receiver set.]]In order to tie up transmitters and receivers with CAD objects in the project workspace, [[EM.Cube]] uses point objects to define transmitters and receivers. These point objects represent the base of the location of transmitters and receivers in the computational domain. Hence, they are grouped together as "Base Sets". You can easily interchange the role of transmitters and receivers in a scene by switching their associated bases. The usefulness of concept of base sets will become apparent later when you place transmitters or receivers on an irregular terrain and adjust their elevation. </td></tr></table>
To create a new base set, right click on In the Receiver Set dialog, there is a drop-down list labeled '''Base SetsSelected Element''' item , which contains a list of Navigation Tree and select '''Insert Base Setall the individual receivers belonging to the receiver set.At the end of an SBR simulation, the button labeled {{key|Show Ray Data}} becomes enabled..''' A Clicking this button opens the Ray Data dialog for setting up , where you can see a list of all the Base Set properties opens upreceived rays at the selected receiver and their computed characteristics.
# Enter a name for If you choose the base "user defined antenna" option for your receiver set and change , it indeed consists of a basic "Receiver Chain" that contains a receive antenna connected via a segment of transmission line to the default blue color if low-noise amplifier (LNA) that is terminated in a matched load. The receiver set's property dialog allows you wishto define the basic receiver chain. It is useful Click the {{key|Receiver Chain}} button of the Receiver Set dialog to differentiate open the base sets associated with transmitters receiver chain dialog. As shown in the figure below, you can specify the characteristics of the LNA such as its gain and receivers by their colornoise figure in dB as well as the characteristics of the transmission line segment that connects the antenna to the LNA.# Click Note that the receiving antenna characteristics are automatically filled from using contents of the radiation file. You have to enter values for antenna's ''OK'Brightness Temperature'' button ' as well as the temperature of the transmission line and the receiver's ambient temperature. The effective '''Receiver Bandwidth''' is assumed to close be 100MHz, which you can change for the Base Set Dialogpurpose of noise calculations. The Receive Chain dialog calculates and reports the "Noise Power" and "Total Receiver Chain Gain" based on your input. At the end of an SBR simulation, the receiver power and signal-noise ratio (SNR) of the selected receiver are calculated and they are reported in the receiver set dialog in dBm and dB, respectively. You can examine the properties of all the individual receivers and all the individual rays received by each receiver in your receiver set using the "Selected Element" drop-down list.
Once a base set node has been added to the Navigation Tree, it becomes the active node for new object drawing<table><tr><td> [[File:NewRxChain. Under base sets, you can only draw point objectspng|thumb|left|720px|EM. All other object creation tools are disabled. A Terrano's point is initially drawn on the XY plane. Make sure to change the Z-coordinate of your radiator, otherwise, it will fall on the global ground at z = 0. You can also create arrays of base points under the same base set. This is particularly useful for setting up receiver grids to compute coverage maps. Simply select a point object and click the '''Array Tool''' of '''Tools Toolbar''' or use the keyboard shortcut "A". Enter values for the X, Y or Z spacing as well as the number of elements along these three directions in the Array Dialog. In most propagation scenes you are interested in 2D horizontal arrays along a fixed Z coordinate (parallel to the XY plane)chain dialog.]] </td></tr></table>
=== Defining Transmitter Sets Modulation Waveform and Detection ===
A short dipole is the closest thing to an omni-directional radiatorEM. The direction or orientation of the short dipole determines its polarization. In many applications, Terrano allows you may rather want to use define a directional antenna digital modulation scheme for your transmittercommunication link. You can model a radiating structure using [[EM.Cube]]'s FDTD, Planar, MoM3D or PO modules and generate a 3D radiation pattern data file for it. These data There are stored currently 17 waveforms to choose from in a specially formatted file with a "'''.RAD'''" extension, which contains columns of spherical φ and θ angles as well as the real and imaginary parts of the complex-valued far field components '''E<sub>θ</sub>''' and '''E<sub>φ</sub>'''. The θ- and φ-components of the far-zone electric field determine the polarization of the transmitting radiator. receiver set property dialog:
To define a directional transmitter radiator, you need to select the "User Defined" option in the "Radiator" section of the Transmitter Dialog. You can do this either at the time of creating a transmitter set, or afterwards by opening the property dialog of the transmitter set. In the "Custom Pattern [[Parameters]]", click the '''Import Pattern''' button to set the path for the radiation data file. This opens up the standard [[Windows]] Open dialog, with the default file type or extension set to ".RAD". Browse your folders to find the right data file. A radiation pattern file usually contains the value of "Total Radiated Power" in its file header. This is used by default for power calculations in the SBR simulation. However, you can check the box labeled "'''Custom Power'''" and enter a value for the transmitter power in Watts. [[EM.Cube]] can also rotate the imported radiation pattern arbitrarily. In this case, you need to specify the '''Rotation''' angles in degrees about the X*OOK*M-, Yary ASK*Coherent BFSK*Coherent QFSK*Coherent M- and Zary FSK*Non-axes. Note that these rotations are performed sequentially and in order: first a rotation about the XCoherent BFSK*Non-Coherent QFSK*Non-Coherent M-ary FSK*BPSK*QPSK*Offset QPSK*M-axis, then a rotation about the Yary PSK*DBPSK*pi/4 Gray-axis, and finally a rotation about the ZCoded DQPSK*M-axisary QAM*MSK*GMSK (BT = 0. 3)
[[File:PROP19In the above list, you need to specify the '''No. Levels (1M)''' for the Mary modulation schemes, from which the '''No. Bits per Symbol''' is determined. You can also define a bandwidth for the signal, which has a default value of 100MHz.png]] [[File:PROP20Once the SNR of the signal is found, given the specified modulation scheme, the E<sub>b</sub>/N<sub>0</sub> parameter is determined, from which the bit error rate (1BER)is calculated.png]]
Figure 1The Shannon â Hartley Equation estimates the channel capacity: [[Propagation Module]]'s Transmitter dialog with a user defined radiator selected.
<math> C === Multiple Transmitters vs. Antenna Arrays ===B \log_2 \left( 1 + \frac{S}{N} \right) </math>
[[EM.Cube]]'s SBR simulations are fully coherent and 3D-polarimetric. This means that where B in the phase and polarization of all the rays are maintained and processed during their bounces bandwidth in the scene. Your propagation scene can have more than one transmitter. During an SBR simulationHz, all the rays emanating from all the transmitters are traced in the propagation scene. All the received rays at a given receiver location are summed coherently and vectorially. This C is based on the principle of linear superposition. All the transmitters belonging to the same transmitter set have the same radiation properties. They are either parallel short dipole radiators with the same current amplitudes and phases, or parallel user defined radiators with identical radiation patterns. As these transmitters are placed at different spatial locations, they effectively form an antenna array with identical elements. The array factor is simply determined by the coordinates of the base points. If you want to have different amplitude or phases, then you need to define different transmitter setschannel capacity (maximum data rate) expressed in bits/s.
If that radiators are indeed the elements The spectral efficiency of an actual antenna array with a half wavelength spacing or so, we recommend that you import the radiation pattern of the array structure instead and replace the whole multi-radiator system with a single point transmitting radiator in your propagation scene. This case channel is usually encountered in MIMO systems, and using an equivalent point transmitter is an acceptable approximation because the total size of the array aperture is usually much smaller than the dimensions of your propagation scene and its representative length scales. In that case, you need to position the equivalent point radiator at the radiation center of the antenna array. This depends on the physical structure of the antenna array. However, keep in mind that any reasonable guess may still provide a good approximation without any significant error in the received ray data. defined as
<math> \eta === Defining Receiver Sets ===\log_2 \left( 1 + \frac{S}{N} \right) </math>
Receivers act as observables in a propagation scene. The objective quantity E<sub>b</sub>/N<sub>0</sub> is the ratio of a SBR simulation is energy per bit to calculate the far-zone electric fields and the total received noise power at the location of a receiverspectral density. In that sense, receivers indeed act as field observation points. You need to define at least one receiver in the scene before you can run It is a SBR simulation. You define the receivers measure of your scene by associating them with SNR per bit and is calculated from the base sets you have already defined in the project workspace. Unlike transmitters that usually one or few, a typical propagation scene may involve a large number of receivers. To generate a wireless coverage map, you need to define an array of points as your base set. following equation:
To define a new Receiver Set, go to the Observables section of the Navigation Tree, right click on the '''Receivers''' item and select '''Insert Receiver...''' A dialog opens up that contains a default name for the new Receiver Set as well as a dropdown list labeled '''Select Radiator Set'''. In this list you will see all the available base sets that you have already define in the project workspace. Select and designate the desired base set as the receiver set. Note that if the base set contains more than one point, all of them are designated as receivers. After defining a receiver set, the points change their color to the receiver color, which is yellow by default. The first element of the set is represented by a larger ball of the same color indicating that it is the selected receiver in the scene. The Receiver Set Dialog is also used to access individual receivers of the set for data visualization at the end of a simulation. At the end of an SBR simulation, the button labeled "Show Ray Data" becomes enabled. Clicking this button opens the Ray Data Dialog, where you can see a list of all the received rays at the selected receiver and their computed characteristics. <math> \frac{E_b}{N_0} = \frac{ 2^\eta - 1}{\eta} </math>
[[File:PROP21(1)where η is the spectral efficiency.png]] [[File:PROP22.png]]
Figure 1: [[Propagation Module]]'s Receiver dialogThe relationship between the bit error rate and E<sub>b</sub>/N<sub>0</sub> depends on the modulation scheme and detection type (coherent vs.non-coherent). For example, for coherent QPSK modulation, one can write:
<math> P_b === Defining Field Sensors ===0.5 \; \text{erfc} \left( \sqrt{ \frac{E_b}{N_0} } \right) </math> where P<sub>b</sub> is the bit error rate and erfc(x) is the complementary error function:
[[File:PMOM90.png|thumb|[[Propagation Module]]'s Field Sensor dialog]]As an asymptotic electromagnetic field solver, the SBR simulation engine can compute the electric and magnetic field distributions in a specified plane. In order to view these field distributions, you must first define field sensor observables before running the SBR simulation. To do that, right click on the '''Field Sensors''' item in the '''Observables''' section of the Navigation Tree and select '''Insert New Observable...'''. The Field Sensor Dialog opens up. At the top of the dialog and in the section titled '''Sensor Plane Location''', first you need to set the plane of field calculation. In the dropdown box labeled '''Direction''', you have three options X, Y, and Z, representing the"normals" to the XY, YZ and ZX planes, respectively. The default direction is Z, i.<math> \text{erfc}(x) = 1-\text{erf}(x) = \frac{2}{\sqrt{\pi}} \int_{x}^{\infty} e. XY plane parallel to the substrate layers. In the three boxes labeled '''Coordinates''', you set the coordinates of the center of the plane. Then, you specify the '''Size''' of the plane in project units, and finally set the '''Number of Samples''' along the two sides of the sensor plane. The larger the number of samples, the smoother the near field map will appear. ^{-t^2} dt </math>
In the section titled Output Settings, you can also select the field map type from two options: The '''ConfettiMinimum Required SNR''' parameter is used to determine link connectivity between each transmitter and '''Cone'''receiver pair. The former produces an intensity plot for field amplitude and phase, while the latter generates a 3D vector plot. In the confetti case, If you have an option to check the box labeled '''Data InterpolationGenerate Connectivity Map'''in the receiver set property dialog, which creates a smooth and blended (digitally filtered) binary map. In the cone case, you can set the size of the vector cones that represent the field directionpropagation scene is generated by EM. At the end of Terrano, in which one color represents a sweep simulation, multiple field map are produced closed link and added to another represent no connection depending on the Navigation Tree. You can animate these maps. However, during the sweep only one field selected color map type is stored, either of the E-field or H-fieldgraph. You can choose the field type for multiple plots using the radio buttons in EM.Terrano also calculates the section titled '''Field Display - Multiple PlotsMax Permissible BER'''. The default choice is corresponding to the E-fieldspecified minimum required SNR and displays it in the receiver set property dialog.
Once you close the Field Sensor dialog, its name is added under the '''Field Sensors''' node of the Navigation Tree=== A Note on EM. At the end of a SBR simulation, the field sensor nodes in the Navigation Tree become populated by the magnitude and phase plots of the three vectorial components of the electric ('''E''') and magnetic ('''H''Terrano') field as well as the total electric and magnetic fields defined in the following manner:s Native Dipole Radiators ===
When you define a new transmitter set or a new receiver set, EM.Terrano assigns a vertically polarized half-wave dipole radiator to the set by default. The radiation pattern of this native dipole radiators is calculated using well-know expressions that are derived based on certain assumptions and approximations. For example, the far-zone electric field of a vertically-polarized dipole antenna can be expressed as:<math> \mathbf{|E_{tot}|} = \sqrt{|E_x|^2 + |E_y|^2 + |E_z|^2} </math>
:<math> E_\mathbftheta(\theta,\phi) \approx j\eta_0 I_0 \frac{|H_e^{tot-jk_0 r}|} = {2\sqrtpi r} \left[ \frac{\text{cos} \left( \frac{k_0 L}{|H_x|^2 + |H_y|^2 + |H_z|^} \text{cos} \theta \right) - \text{cos} \left( \frac{k_0 L}{2} \right) }{\text{sin}\theta} \right] </math><!--[[File:PMOM88.png]]-->
=== Computing Radiation Patterns In SBR ===<math> E_\phi(\theta,\phi) \approx 0 </math>
Coming Soon..where k<sub>0</sub> = 2π/λ<sub>0</sub> is the free-space wavenumber, λ<sub>0</sub> is the free-space wavelength, η<sub>0</sub> = 120π Ω is the free-space intrinsic impedance, I<sub>0</sub> is the current on the dipole, and L is the length of the dipole.
== Scene Discretization & Adjustment ==The directivity of the dipole antenna is given be the expression:
=== The Need For Discretization Of Propagation Scene ===<math> D_0 \approx \frac{2}{F_1(k_0L) + F_2(k_0L) + F_3(k_0L)} \left[ \frac{\text{cos} \left( \frac{k_0 L}{2} \text{cos} \theta \right) - \text{cos} \left( \frac{k_0 L}{2} \right) }{\text{sin}\theta} \right]^2 </math>
In a typical SBR simulation, a ray is traced from the location of the source until it hits a scatterer. The [[SBR Method|SBR method]] assumes that the ray hits either a flat facet of the scatterer or one of its edges. In the case of hitting a flat facet, the specular point is used to launch new reflected and transmitted rays. The surface of the facet is treated as an infinite dielectric medium interface, at which the reflection and transmission coefficients are calculated. In the case of hitting an edge, new diffracted rays are generated in the scene. However, only those who reach a nearby receiver in their line of sight are ever taken into account. In other words, diffractions are treated locally.with
[[EM.Cube]]'s [[Propagation Module]] allows you to draw any type of surface or solid CAD objects under impenetrable and penetrable surface groups. Some of these objects have flat faces such as boxes, pyramids, rectangle or triangle strips, etc. Some others contain curved surfaces or curved boundaries such as cylinders, cones, etc. All the non<math> F_1(x) = \gamma + \text{ln}(x) -flat surfaces have to be discretized in the form of a collection of smaller flat facets. [[EM.Cube]] uses a triangular surface mesh generator to discretize the penetrable and impenetrable [[Surface Objects|surface objects]] of your propagation scene. This mesh generator is very similar to the ones used in [[EM.Cube]]'s two other modules: MoM3D and Physical Optics C_i(POx). </math>
You can build a variety of surface and <math> F_2(x) = \frac{1}{2} \text{sin}(x) \left[[Solid Objects|solid objects]] using [[EM.Cube]]'s native "Curve" CAD objects like lines, polylines, circles, etc. You can use tools like Extrude, Loft, StripS_i(2x) -Sweep, Pipe-Sweep, etc. to transform curves into surface or [[Solid Objects|solid objects]2S_i(x) \right]. '''However, keep in mind that all the "Curve" CAD objects are ignored by the SBR mesh generator and are therefore not sent to the simulation engine.''' </math>
<math> F_3(x) === Viewing SBR Mesh ===\frac{1}{2} \text{cos}(x) \left[ \gamma + \text{ln}(x/2) + C_i(2x) - 2C_i(x) \right] </math>
You can view and examine the discretized version of your scene objects as they are sent to the SBR simulation engine. To view the mesh, click the '''Mesh''' [[File:mesh_tool.png]] button of the Simulate Toolbar or select '''Simulate > Discretization > Show Mesh''', or use the keyboard shortcut '''Ctrl+M'''. A triangular surface mesh of your physical structure appears in the project workspace. In this case, [[EM.Cube]] enters it mesh view mode. You can perform view operations like rotate view, pan, zoom, etc. But you cannot select objects, or move them or edit their properties. To get out of the Mesh View and return to [[EM.Cube]]'s Normal View, press the '''Esc Key''' of the keyboard, or click the Mesh button of the Simulate Toolbar once again, or go to the Simulate Menu and deselect the '''Discretization >''' '''Show Mesh''' item.
You can adjust the mesh resolution and increase the geometric fidelity of discretization by creating more and finer triangular facetswhere γ = 0. On 5772 is the other handEuler-Mascheroni constant, you may want to reduce the mesh complexity and send to the SBR engine only a few coarse facets to model your buildings. To adjust the mesh resolution, open the Mesh Settings Dialog by clicking the '''Mesh Settings''' [[File:mesh_settings.png]] button of the Simulate Toolbar or select '''Simulate > Discretization >''' '''Mesh Settings...'''. This dialog provides a single [[parameters]]: '''Edge Length'''., which has a default value of 100 project units. If you C<sub>i</sub>(x) and S<sub>i</sub>(x) are already in the Mesh View Mode cosine and open the Mesh Settings Dialogsine integrals, you can see the effect of changing the edge length using the '''Apply''' button. Click OK to close the dialog.respectively:
Note that unlike [[EM.Cube]]'s other computational modules that express the default mesh density based on the wavelength, the resolution of the SBR mesh generator is expressed in project length units. The default edge length value of 100 units might be too large for non-flat objects. You may have to use a lower value to capture the curvature of your curved structures adequately.
[[File:prop_manual<math> C_i(x) = -29.png]]\int_{x}^{\infty} \frac{ \text{cos} \tau}{\tau} d\tau </math>
Figure 1: [[Propagation Module]]'s Mesh Settings dialog.<math> S_i(x) = \int_{0}^{x} \frac{ \text{sin} \tau}{\tau} d\tau </math>
=== Special Discretized Object Types ===
In [[EM.Cube]]the case of a half-wave dipole, terrain objects are represented by and saved as special L = "lambda;Tessellated" objects with quadrilateral cells<sub>0</sub>/2, and D<sub>0</sub> = 1. This is true of terrain objects that you create yourself using [[EM643.Cube]]'s Terrain Generator as well as all Moreover, the terrain objects that you import from external files to your project. The center input impedance of each cell represents the terrain elevation at that pointdipole antenna is Z<sub>A</sub> = 73 + j42. Tessellated objects are considered as discretized objects by [[EM5 Ω.Cube]] and they These dipole radiators are not meshed one more time by the SBR mesh generator. Each quadrilateral cell is divided into two triangular cells before being passed connected via 50Ω transmission lines to the SBR simulation enginea 50Ω source or load. Therefore, when using [[EM.Cube]]'s Terrain Generator to create there is always a new terrain object, you have to pay special attention to the resolution certain level of impedance mismatch that violates the terrain object as it determines the total number of terrain facets sent to the simulation engine. A high resolution terrain, although looking better and more realistic, may easily lead to an enormous computational problemconjugate match condition for maximum power.
You can use <table><tr><td> [[EMFile:Dipole radiators.Cube]]'s "Polymesh" tool to discretize solid and surface CAD objects. You can manually control the mesh characteristics of polymesh objects including inserting new nodes on faces and edges or deleting existing nodes. In addition, [[png|thumb|720px|EM.Cube]]Terrano's Solid Generator native half-wave dipole transmitter and Surface Generator tools create ploymesh solids and surfaces, respectivelyreceiver. Like tessellated object, polymesh objects are also considered as discretized objects by [[EM.Cube]] and they are not meshed again by the SBR mesh generator. </td></tr></table>
=== SBR Mesh Rules On the other hand, we you specify a user-defined antenna pattern for the transmitter or receiver sets, you import a 3D radiation pattern file that contains all the values of E<sub>&theta; Considerations ===</sub> and E<sub>φ</sub> for all the combinations of (θ, φ) angles. Besides the three native dipole radiators, [[EM.Cube]] also provides 3D radiation pattern files for three X-, Y- and Z-polarized half-wave resonant dipole antennas. These pattern data were generated using a full-wave solver like [[EM.Libera]]'s wire MOM solver. The names of the radiation pattern files are:
Coming Soon* DPL_STD_X.RAD* DPL_STD_Y.RAD* DPL_STD_Z.RAD
=== Adjusting Block Elevation On Terrain ===and they are located in the folder "\Documents\EMAG\Models" on your computer. Note that these are full-wave simulation data and do not involve any approximate assumptions. To use these files as an alternative to the native dipole radiators, you need to select the '''User Defined Antenna Pattern''' radio button as the the radiator type in the transmitter or receiver set property dialog.
In [[EM.Cube]], buildings and all other CAD objects are initially created === A Note on the XY plane by default. In other words, the Z-coordinate Rotation of the local coordinate system (LCS) of all blocks is set to zero until you change them. As long as you use the global ground, all is fine as your buildings are seated on the ground. When your propagation scene has an irregular terrain, you want to place your buildings on the terrain and not buried under it. Buildings in [[EM.Cube]] are not adjusted to the terrain elevation automatically. You need to instruct [[EM.Cube]] to do so.Antenna Radiation Patterns ===
To update the building positions EM.Terrano's Transmitter Set dialog and adjust their elevation Receiver Set dialog both allow you to the underlying terrainrotate an imported radiation pattern. In that case, right click on you need to specify the '''TerrainRotation''' item of angles in degrees about the Navigation Tree X-, Y- and select '''Adjust Scene Elevation''' from the context menuZ-axes. All the blocks in the scene It is important to note that these rotations are automatically elevated performed sequentially and in the Z direction such that their bases sit on following order: first a rotation about the terrainX-axis, then a rotation about the Y-axis, and finally a rotation about the Z-axis. In effectaddition, all the blocks rotations are translated along performed with respect to the global Z axis by proper amounts such that their "rotated" local Z coordinate equals systems (LCS). In other words, the Zfirst rotation with respect to the local X-elevation of axis transforms the underlying terrain objectXYZ LCS to a new primed X<sup>′</sup>Y<sup>′</sup>Z<sup>′</sup> LCS. This feature The second rotation is particularly useful if you change performed with respect to the location of new Y<sup>′</sup>-axis and transforms the terrain or import X<sup>′</sup>Y<sup>′</sup>Z<sup>′</sup> LCS to a new terrain after double-primed X<sup>′′</sup>Y<sup>′′</sup>Z<sup>′′</sup> LCS. The third rotation is finally performed with respect to the blocks have been creatednew Z<sup>′′</sup>-axis. The figures below shows single and double rotations.
Note<table><tr><td> [[File: You have to make sure that the resolution of your terrain, its fluctuation scale and building dimensions are all comparablePROP22B. Otherwise, on png|thumb|300px|The local coordinate system of a highlinear dipole antenna.]] </td><td> [[File:PROP22C.png|thumb|600px|Rotating the dipole antenna by +90° about the local Y-resolution, rapidly varying terrain, you will have buildings whose bottoms are in contact with axis.]] </td></tr></table><table><tr><td> [[File:PROP22D.png|thumb|720px|Rotating the terrain only at a few points dipole antenna by +90° about the local X-axis and parts of them hang in then by -45° by the airlocal Y-axis.]] </td></tr></table>
[[File:prop_adjust1_tn.png|400px]] [[File:prop_adjust2_tn.png|400px]]=== Adjustment of Tx/Rx Elevation above a Terrain Surface ===
Figure: A Scene When your transmitters or receivers are located above a flat terrain like the global ground, their Z-coordinates are equal to their height above the ground, as the terrain elevation is fixed and equal to zero everywhere. In many propagation modeling problems, your transmitters and receivers may be located above an irregular terrain with Buildings varying elevation across the scene. In that case, you may want to place your transmitters or receivers at a certain height above the underlying ground. The Z-coordinate of a transmitter or receiver is now the sum of the terrain elevation at the base point and Terrain Before the specified height. EM.Terrano gives you the option to adjust the transmitter and After Adjusting receiver sets to the terrain elevation. This is done for individual transmitter sets and individual receiver sets. At the top of the Transmitter Dialog there is a check box labeled "'''Adjust Tx Sets to Terrain Elevation'''". Similarly, at the top of the Receiver Dialog there is a check box labeled "'''Adjust Rx Sets to Terrain Elevation'''". These boxes are unchecked by default. As a result, your transmitter sets or receiver sets coincide with their associated base points in the project workspace. If you check these boxes and place a transmitter set or a receiver set above an irregular terrain, the transmitters or receivers are elevated from the location of their associated base points by the amount of terrain elevation as can be seen in the figure below.
=== Transmitters & Receivers Above An Irregular Terrain ===To better understand why there are two separate sets of points in the scene, note that a point array (CAD object) is used to create a uniformly spaced base set. The array object always preserves its grid topology as you move it around the scene. However, the transmitters or receivers associated with this point array object are elevated above the irregular terrain and no longer follow a strictly uniform grid. If you move the base set from its original position to a new location, the base points' topology will stay intact, while the associated transmitters or receivers will be redistributed above the terrain based on their new elevations.
In <table><tr><td> [[EMImage:PROP MAN8.Cube]], all the transmitters png|thumb|left|640px|A transmitter (red) and receivers are tied up with point objects in the project workspace. These point objects are grouped and organized in base sets. When you move the point objects or change their coordinates, all of their associated transmitters or receivers immediately follow them to the new location. For example, you usually define a grid of receivers using (yellow) adjusted above a plateau terrain surface. The underlying base set that is made up of a uniformly spaced array of points point sets (blue and spread them in your scene. All of these receivers have the same height because their orange dots) associated base points all have with the same Z-coordinate. When your adjusted transmitters and receivers are located above a flat on the terrain like the global ground, their Z-coordinates are equal to their height above also visible in the ground, as the terrain elevation is fixed and equal to zero everywherefigure. The same is true for transmitters, too. ]] </td></tr></table>
In many propagation modeling problems, your transmitters and receivers may be located above an irregular terrain with varying elevation across == Discretizing the scene. In that case, you may want to place your transmitters or receivers at a certain height above the underlying ground. The Z-coordinate of a transmitter or receiver is now the sum of the terrain elevation at the base point and the specified height. [[Propagation Scene in EM.Cube]] gives you the option to adjust the transmitter and receiver sets to the terrain elevation. This is done for individual transmitter sets and individual receiver sets. At the top of the Transmitter Dialog there is a check box labeled "'''Adjust Tx Sets to Terrain Elevation'''". Similarly, at the top of the Receiver Dialog there is a check box labeled "'''Adjust Rx Sets to Terrain Elevation'''". These boxes are unchecked by default. As a result, your transmitter sets or receiver sets coincide with their associated base points in the project workspace. If you check these boxes and place a transmitter set or a receiver set above an irregular terrain, the transmitters or receivers are elevated from the location of their associated base points by the amount of terrain elevation as can be seen in the figure below. Terrano ==
To better understand why there are two separate sets of points in the scene, note that a point array (CAD object) is used === Why Do You Need to create a uniformly spaced base set. The array object always preserves its grid topology as you move it around the scene. However, the transmitters or receivers associated with this point array object are elevated above the irregular terrain and no longer follow a strictly uniform grid. If you move the base set from its original position to a new location, the base points' topology will stay intact, while the associated transmitters or receivers will be redistributed above Discretize the terrain based on their new elevations.Scene? ===
[[File:prop_txrx1_tnEM.png|400px]] [[File:prop_txrx2_tnTerrano's SBR solver uses a method known as Geometrical Optics (GO) in conjunction with the Uniform Theory of Diffraction (UTD) to trace the rays from their originating point at the source to the individual receiver locations. Rays may hit obstructing objects on their way and get reflected, diffracted or transmitted. EM.Terrano's SBR solver can only handle diffraction off linear edges and reflection from and transmission through planar interfaces. When an incident ray hits the surface of the obstructing object, a local planar surface assumption is made at the specular point. The assumptions of linear edges and planar facets obviously work in the case of a scene with cubic buildings and a flat global ground.png|400px]]
Figure: Transmitters and receivers adjusted above an uneven In many practical scenarios, however, your buildings may have curved surfaces, or the terrain may be irregular. EM.Terrano allows you to draw any type of surface or solid geometric objects such as cylinders, cones, etc. under impenetrable and their associated base setspenetrable surface groups or penetrable volumes. EM.Terrano's mesh generator creates a triangular surface mesh of all the objects in your propagation scene, which is called a facet mesh. Even the walls of cubic buildings are meshed using triangular cells. This enables EM.Terrano to properly discretize composite buildings made of conjoined cubic objects.
== Running Unlike [[EM.Cube]]'s other computational modules, the density or resolution of EM.Terrano's surface mesh does not depend on the operating frequency and is not expressed in terms of the wavelength. The sole purpose of EM.Terrano's facet mesh is to discretize curved and irregular scatterers into flat facets and linear edges. Therefore, geometrical fidelity is the only criterion for the quality of a facet mesh. It is important to note that discretizing smooth objects using a triangular surface mesh typically creates a large number of small edges among the facets that are simply mesh artifacts and should not be considered as diffracting edges. For example, each rectangular face of a cubic building is subdivided into four triangles along the two diagonals. The four internal edges lying inside the face are obviously not diffracting edges. A lot of subtleties like these must be taken into account by the SBR Simulation ==solver to run accurate and computationally efficient simulations.
[[EM.Cube]]'s [[Propagation Module]] offers three types of ray tracing simulations:=== Generating the Facet Mesh ===
* Analysis* Frequency Sweep* Parametric SweepYou can view and examine the discretized version of your scene's objects as they are sent to the SBR simulation engine. You can adjust the mesh resolution and increase the geometric fidelity of discretization by creating more and finer triangular facets. On the other hand, you may want to reduce the mesh complexity and send to the SBR engine only a few coarse facets to model your buildings. The resolution of EM.Terrano's facet mesh generator is controlled by the '''Cell Edge Length''' parameter, which is expressed in project length units. The default mesh cell size of 100 units might be too large for non-flat objects. You may have to set a smaller cell edge length in EM.Terrano's Mesh Settings dialog, along with a lower curvature angle tolerance value to capture the curvature of your curved structures adequately.
An SBR analysis is the simplest ray tracing simulation and involves the following steps<table><tr><td> [[Image:prop_manual-29.png|thumb|left|480px|EM.Terrano's mesh settings dialog.]] </td></tr></table>
# Set the unit of project scene and the frequency of operation. Note that [[EMImage:Info_icon.Cubepng|30px]]Click here to learn more about '''s default project unit is millimeter. When working with the [[Propagation Module]], pay attention to the project unit. Radio propagation problems usually require meter, mile or kilometer as the project unit.Preparing_Physical_Structures_for_Electromagnetic_Simulation# Create the blocks and draw the buildings at the desired locationsWorking_with_EM.# Keep the default ray domain and accept the default global ground or change its material propertiesCube.# Define the base sets (at least one for the transmitter and one for the receiver).# Define the transmitter and receiver(s) using the available base sets.# Run the SBR simulation engine.# Visualize the coverage map and plot other data27s_Mesh_Generators | Working with Mesh Generator]]'''.
You can access the [[Propagation Module]]'s run dialog by clicking the '''Run''' [[FileImage:run_iconInfo_icon.png|30px]] button Click here to learn more about the properties of the '''Simulate Toolbar''' or by selecting '''Simulate > Run.[[Glossary_of_EM.Cube%27s_Simulation-Related_Operations#Facet_Mesh | EM.Terrano's Facet Mesh Generator]]'' or using the keyboard shortcut '''Ctrl+R'''. When you click the '''Run''' button, a new window opens up that reports the different stages of the SBR simulation and indicates the progress of each stage. After the SBR simulation is successfully completed, a message pops up and prompts the completion of the process.
<table><tr><td> [[FileImage:PROP12UrbanCanyon2.png|thumb|left|640px|The facet mesh of the buildings in the urban propagation scene generated by EM.Terrano's Random City wizard with a cell edge length of 100m.]] </td></tr><tr><td> [[Image:UrbanCanyon3.png|thumb|left|640px|The facet mesh of the buildings in the urban propagation scene generated by EM.Terrano's Random City wizard with a cell edge length of 10m.]]</td></tr></table>
Figure 1: [[Propagation Module]]'s Simulation Run dialog== Running Ray Tracing Simulations in EM.Terrano ==
=== SBR Simulation Parameters ===EM.Terrano provides a number of different simulation or solver types:
There are a number of * 3D Field Solver* SBR simulation settings that can be accessed and changed from the SBR Settings Dialog. To open this dialog, click the button labeled '''Settings''' on the right side of the '''Select Engine''' dropdown list in the Run Dialog. [[EM.Cube]]'s SBR simulation engine allows you to separate the physical effects that are calculated during a ray tracing process. You can selectively enable or disable '''Ray Reflection''', '''Ray Transmission''' and '''Ray Diffraction'''. By default, all three effects are checked and included in the computations. Separating these effects sometimes help you better analyze your propagation scene and understand the impact of various blocks in the scene.Channel Analyzer* Log-Haul Channel Analyzer* Communication Link Solver* Radar Link Solver
[[EMThe first three simulation types are described below.Cube]] requires For a finite number description of ray bounces for each original ray emanating from a transmitterEM. This is very important in situations that may involve resonance effects where rays get trapped among certain group of surfaces and may bounce back and forth indefinitely. This is set using the box labeled "Terrano'''Max No. Ray Bounces'''"s Radar Simulator, which has a default value of 10. Note that the maximum number of ray bounces directly affects the computation time as well as the size of output simulation data files. This can become critical for indoor propagation scenes, where most of the rays undergo a large number of reflectionsfollow this link.
As rays travel in the scene and bounce from surfaces, they lose their power and their amplitudes diminish. From === Running a practical point of view, only rays that have power above the receiver sensitivity threshold can be effectively received. Therefore, all the rays whose power fall below a specified power threshold are discarded. The '''Ray Power Threshold''' is specified in dBm and has a default value of Single-100dBm. Keep in mind that the value of this threshold directly affects the accuracy of the simulation results as well as the size of the output data file.Frequency SBR Analysis ===
You can also set Its main solver is the '''Angular Resolution3D SBR Ray Tracer''' of the transmitter rays . Once you have set up your propagation scene in degreesEM. By defaultTerrano and have defined sources/transmitters and observables/receivers for your scene, every transmitter emanates equi-angular ray tubes at you are ready to run a resolution of 1 degreeSBR ray tracing simulation. Lower angular resolutions larger than 1° speed up You set the simulation mode in EM.Terrano's simulation run dialog. A single-frequency SBR analysis is a single-run simulation significantly, but they may compromise and the accuracy. Higher angular resolutions less than 1° increase the accuracy simplest type of the simulating results, but they also increase the computation timeray tracing simulation in EM.Terrano. It involves the following steps:
[[File:PROP13* Set the units of your project and the frequency of operation. Note that the default project unit is '''millimeter'''. Wireless propagation problems usually require meter, mile or kilometer as the project unit.* Create the blocks and draw the buildings at the desired locations.* Keep the default ray domain and accept the default global ground or change its material properties.* Define an excitation source and observables for your project.* If you intend to use transmitters and receivers in your scene, first define the required base sets and then define the transmitter and receiver sets based on them.* Run the SBR simulation engine.* Visualize the coverage map and plot other data.png]]
Figure 1: You can access EM.Terrano's Simulation Run dialog by clicking the '''Run''' [[Propagation ModuleFile:run_icon.png]]button of the 's ''Simulate Toolbar''' or by selecting '''Simulate → Run...''' or using the keyboard shortcut {{key|Ctrl+R}}. When you click the {{key|Run}} button, a new window opens up that reports the different stages of the SBR Engine Settings dialogsimulation and indicates the progress of each stage. After the SBR simulation is successfully completed, a message pops up and prompts the completion of the process.
=== The Coverage Map ===<table><tr><td> [[Image:Terrano L1 Fig16.png|thumb|left|480px|EM.Terrano's simulation run dialog.]] </td></tr></table>
If the associated radiator set is isotropic, so will be the transmitter set<table><tr><td> [[Image:PROP MAN10. By default, an isotropic transmitter has vertical polarizationpng|thumb|left|550px|EM. You can use the '''Polarization''' radio button to select one of the two options: '''Vertical''' or '''Horizontal''Terrano's output message window. If the associated radiator set consists of '''Short Dipole''' or '''User Defined''' radiators, it is indicated in the transmitter property dialog. In the case of a short dipole radiator, you can set a value for the dipole current in Amperes. The radiation resistance of a short dipole of length ''dl'' is given by:]] </td></tr></table>
:<math> R_r = 80\pi^2 \left( \frac{dl}{\lambda_0} \right)^2 </math><!--[[File:eqngr6.png]]-->== Changing the SBR Engine Settings ===
The radiated power There are a number of SBR simulation settings that can be accessed and changed from the Ray Tracing Engine Settings Dialog. To open this dialog, click the button labeled {{key|Settings}} on the right side of the '''Select Simulation or Solver Type''' drop-down list in the Run Dialog. EM.Terrano's SBR simulation engine allows you to separate the physical effects that are calculated during a short dipole carrying a current I<sub>0<ray tracing process. You can selectively enable or disable '''Reflection/sub> is then given by:Transmission''' and '''Edge Diffraction''' in the "Ray-Block Interactions" section of this dialog. By default, ray reflection and transmission and edge diffraction effects are enabled. Separating these effects sometimes help you better analyze your propagation scene and understand the impact of various blocks in the scene.
EM.Terrano allows a finite number of ray bounces for each original ray emanating from a transmitter. This is very important in situations that may involve resonance effects where rays get trapped among multiple surfaces and may bounce back and forth indefinitely. This is set using the box labeled "'''Max No. Ray Bounces'''", which has a default value of 10. Note that the maximum number of ray bounces directly affects the computation time as well as the size of output simulation data files. This can become critical for indoor propagation scenes, where most of the rays undergo a large number of reflections. Two other parameters control the diffraction computations:<math> P_{rad} = \frac{1}{2} R_r |I_0|^2 = 40\pi^2 |I_0|^2 \left( \frac{dl}{\lambda_0} \right)^2 </math><!--[[File:shortdipole'''Max Wedge Angle''' in degrees and '''Min Edge Length''' in project units. The maximum wedge angle is the angle between two conjoined facets that is considered to make them almost flat or coplanar with no diffraction effect. The default value of the maximum wedge angle is 170°. The minimum edge length is size of the common edge between two conjoined facets that is considered as a mesh artifact and not a real diffracting edge. The default value of the minimum edge length is one project units.png]]-->
For isotropic and user defined radiators you can set the '''Input Power''' and '''Phase''' of a transmitter set in Watts and degrees, respectively<table><tr><td> [[Image:PROP MAN11. This can be accessed from the '''Transmitter Chain''png|thumb|left|720px|EM.Terrano' s SBR simulation engine settings dialog, which will be described in detail in the next section. The radiation pattern of the associated radiator set is normalized and used in conjunction with the input power value to create a weighted distribution of transmitted rays. In certain cases like hybrid simulations, you may want to use the actual values of the far field to define the transmitter power rather than a normalized radiation pattern. Note that the pattern (.RAD) file contains the value of total radiated power in its header. In this case, check the box labeled '''"Calculate Power From Radiation Pattern"'''. This is calculated directly from the complex θ and φ components of the far field data by integrating them over the entire space (4π solid angle). Note that this option is available only when the radiator is of the User Defined type. When this box is checked, the transmitter chain button is grayed out. By default, an isotropic transmitter emanates rays uniformly in all directions at the angular resolution specified by the user. A transmitter with a user defined associated radiator may represent a highly directional radiation pattern with the main beam pointing in a certain direction. You can additionally force and limit the '''Angular Extents''' of rays to a certain solid angle around the transmitter. This is especially useful and computationally efficient when the transmitter is on one side of the scene, and all the scatterers and receivers are on the other side. In this case, there is no need to generate rays in all directions. To limit the angular extents of rays, define the Start and End values for both Theta (θ) and Phi (φ) angles. The value of the angular resolution of the rays can be changed from the Run Dialog as will be discussed later.]] </td></tr></table>
In a regular SBR simulationAs rays travel in the scene and bounce from surfaces, they lose their power, you have a transmitter and one or more arrays of receivers in your scenetheir amplitudes gradually diminish. At the end From a practical point of the simulationview, you can visualize the coverage map of the transmitter over only rays that have power levels above the receiver setssensitivity can be effectively received. A coverage map shows Therefore, all the total rays whose power levels fall below a specified power threshold are discarded. The '''Received Ray PowerThreshold''' by each of the receivers and is visualized as specified in dBm and has a colordefault value of -coded intensity plot150dBm. You can visualize Keep in mind that the coverage maps value of individual receiver sets. At this threshold directly affects the end accuracy of a SBR the simulation, each Received Power Coverage Map is listed under the receiver set's name in the Navigation Tree. To display a coverage map, simply click on its entry in the Navigation Tree. The coverage map plot appears in the Main Window overlaid on the scene. A legend box on the right shows the color scale and units (dB). The 3-D coverage maps are displayed results as horizontal confetti above the receivers. If the receivers are packed close to each other, you will see a continuous confetti map. If the receivers are far apart, you will see individual colored squares. You can also visualize coverage maps well as colored 3-D cubes. This may be useful when you set up your receivers in a vertical arrangement or the scene has a highly uneven terrain. To change the type of coverage map visualization, open the receiver set's property dialog and select the desired option for '''Coverage Map: Confetti''' or '''Cube''' in the '''"Visualization Options"''' section size of the dialogoutput data file.
[[File:prop_run11_tnYou can also set the '''Ray Angular Resolution''' of the transmitter rays in degrees.png|400px]] [[File:prop_run12_tnBy default, every transmitter emanates equi-angular ray tubes at a resolution of 1 degree. Lower angular resolutions larger than 1° speed up the SBR simulation significantly, but they may compromise the accuracy. Higher angular resolutions less than 1° increase the accuracy of the simulating results, but they also increase the computation time. The SBR Engine Settings dialog also displays the '''Recommended Ray Angular Resolution''' in degrees in a grayed-out box. This number is calculated based on the overall extents of your computational domain as well as the SBR mesh resolution. To see this value, you have to generate the SBR mesh first. Keeping the angular resolution of your project above this threshold value makes sure that the small mesh facets at very large distances from the source would not miss any impinging ray tubes during the simulation.png|400px]]
Figure: Received power coverage map: EM.Terrano gives a few more options for the ray tracing solution of your propagation problem. For instance, it allows you to exclude the direct line-of-sight (LeftLOS) confetti style, and rays from the final solution. There is a check box for this purpose labeled "Exclude direct (RightLOS) cube stylerays from the solution", which is unchecked by default. EM.Terrano also allows you to superpose the received rays incoherently. In that case, the powers of individual ray are simply added to compute that total received power. This option in the check box labeled "Superpose rays incoherently" is disabled by default, too.
You can change At the settings end of a ray tracing simulation, the coverage map by right clicking on its entry in the Navigation Tree electric field of each individual ray is computed and selecting '''Propertiesreported.By default, the actual received ray fields are reported, which are independent of the radiation pattern of the receive antennas.EM.Terrano provides a check box labeled "Normalize ray''' or by doubles E-clicking field based on the legend box. In the Output Plot Settings dialogreceiver pattern", you can choose from one of three Color Map options: '''Default''', '''Rainbow''' and '''Grayscale'''. The visualization plot uses which is unchecked by default values for the color scale. In the section titled "Limits"If this box is checked, you can choose the radio button labeled '''User Defined'''. Then, you have field of each ray is normalized so as to enter new values for reflect that effect of the receiver antenna'''Lower''' and '''Upper''' Limits s radiation pattern. The received power of each ray is calculated from the plot. You can also show or hide the Legend Box or change its '''Background''' and '''Foreground''' colors by clicking the buttons provided for this purpose.following equation:
[[File:prop_run4.png]]<math> P_{ray} = \frac{ | \mathbf{E_{norm}} |^2 }{2\eta_0} \frac{\lambda_0^2}{4\pi} </math>
Output Plot SettingsIt can be seen that if the ray's E-field is not normalized, the computed ray power will correspond to that of a polarization matched isotropic receiver.
=== The Ray Data Polarimetric Channel Analysis ===
At the end of In a 3D SBR simulation, each receiver receives a transmitter shoots a large number of rays. Some receivers may not receive any rays at in alldirections. You can visualize all the The electric fields of these rays received are polarimetric and their strength and polarization are determined by a certain receiver from the active transmitter designated radiation pattern of the scenetransmit antenna. To do this, right click The rays travel in the '''Receivers''' item of propagation scene and bounce from the Navigation Tree. From ground and buildings or other scatterers or get diffracted at the context menu select '''Show Received Rays'''. All building edges until they reach the rays received by the currently selected receiver location of the scene are displayed in the scenereceivers. Each individual ray has its own vectorial electric field and power. The electric fields of the received rays are identified by labels, are ordered by their power then superposed coherently and have different colors for better visualization. You can display polarimetrically to compute the total field at the rays for only one receiver at a timelocations. The receiver set property dialog has a list designated radiation pattern of all the individual receivers belonging is then used to that set. To display compute the rays total received power by another each individual receiver, you have to change the '''Selected Receiver''' in the receiver set's property dialog. If you keep the mouse focus on this dropdown list and roll your mouse scroll wheel, you can scan the selected receivers and move the rays from one receiver to the next in the list. To remove the visualized rays from the scene, right click the Receivers item of the Navigation Tree again and from the context menu select '''Hide Received Rays'''.
[[File:prop_run5_tnFrom a theoretical point of view, the radiation patterns of the transmit and receive antennas are independent of the propagation channel characteristics. For the given locations of the point transmitters and receivers, one can assume ideal isotropic radiators at these points and compute the polarimetric transfer function matrix of the propagation channel. This matrix relates the received electric field at each receiver location to the transmitted electric field at each transmitter location. In general, the vectorial electric field of each individual ray is expressed in the local standard spherical coordinate system at the transmitter and receiver locations. In other words, the polarimetric channel matrix expresses the '''E<sub>θ</sub>''' and '''E<sub>φ</sub>''' field components associated with each ray at the receiver location to its '''E<sub>θ</sub>''' and '''E<sub>φ</sub>''' field components at the transmitter location. Each ray has a delay and θ and φ angles of departure at the transmitter location and θ and φ angles of departure at the receiver location.png|800px]]
Visualization To perform a polarimatric channel characterization of received rays at your propagation scene, open EM.Terrano's Run Simulation dialog and select '''Channel Analyzer''' from the location drop-down list labeled '''Select Simulation or Solver Type'''. At the end of the selected simulation, a large ray database is generated with two data files called "sbr_channel_matrix.DAT" and "sbr_ray_path.DAT". The former file contains the delay, angles of arrival and departure and complex-valued elements of the channel matrix for all the individual rays that leave each transmitter and arrive at each receiver. The latter file contains the geometric aspects of each ray such as hit point coordinates.
You can also view the ray [[parameters]] by opening the property dialog of a receiver set. By default, the first receiver of the set is always selected. You can select any other receiver from the drop=== The "Near Real-down list labeled '''Selected Receiver'''. If you click the button labeled '''Show Ray Data''', a new dialog opens up with a table that contains all the received rays at the selected receiver and their [[parameters]]:Time" Polarimatrix Solver ===
* Delay is the total time delay that After EM.Terrano's channel analyzer generates a ray experiences travelling from database that characterizes your propagation channel polarimetrically for all the combinations of transmitter to the and receiver after all locations, a ray tracing solution of the reflections, transmissions and diffractions and is expressed propagation problem can readily be found in nanoseconds.* Ray Field is almost real time by incorporating the received electric field at effects of the receiver location due to a specific ray radiation patterns of transmit and is given in dBV/mreceive antennas.* Ray Power This is done using the received power at '''Polarimatrix Solver''', which is the receiver due to a specific ray and is given third option of the drop-down list labeled '''Select Simulation or Solver Type''' in dBmEM.Terrano's Run Simulation dialog.* Angles The results of Arrival are the θ Polarimatrix and φ angles 3D SBR solvers must be identical from a theoretical point of view. However, there might be small discrepancies between the incoming ray at the local spherical coordinate system of the receivertwo solutions due to roundoff errors.
The Ray Data Dialog also shows Using the '''Total Received Power''' in dBm and '''Total Received Field''' in dBV/m due to all the rays received by the receiver. You Polarimatrix solver can sort the rays based on their delay, field, power, etc. To do so, simply click on the grey column label in the table lead to sort a significant reduction of the rays total simulation time in ascending order based on the selected parameter. You can also select any ray by clicking on its '''ID''' sweep simulations that involve a large number of transmitters and highlighting its row in the tablereceivers. In that case, Certain simulation modes of EM.Terrano are intended for the selected rays is highlighted Polarimatrix solver only as will be described in the Project Workspace and all the other rays become thin (faded)next section.
{{Note: The rays are summed up coherently at | In order to use the receiverPolarimatrix solver, you must first generate a ray database of your propagation scene using EM.Terrano's Channel Analyzer.}}
[[File:prop_run6_tn=== EM.png|800px]]Terrano's Simulation Modes ===
Figure: Analyzing a selected ray from the ray data dialogEM.Terrano provides a number of different simulation modes that involve single or multiple simulation runs:
{| class="wikitable"|-! scope== Plotting Other "col"| Simulation Results Mode! scope="col"| Usage! scope="col"| Which Solver?! scope="col"| Frequency ! scope="col"| Restrictions|-| style="width:120px;" | [[#Running a Single-Frequency SBR Analysis | Single-Frequency Analysis]]| style="width:180px;" | Simulates the propagation scene "As Is"| style="width:150px;" | SBR, Channel Analyzer, Polarimatrix, Radar Simulator| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | None|-| style="width:120px;" | [[Parametric_Modeling_%26_Simulation_Modes_in_EM.Cube#Running_Frequency_Sweep_Simulations_in_EM.Cube | Frequency Sweep]]| style="width:180px;" | Varies the operating frequency of the ray tracer | style="width:150px;" | SBR, Channel Analyzer, Polarimatrix, Radar Simulator| style="width:120px;" | Runs at a specified set of frequency samples| style="width:300px;" | None|-| style="width:120px;" | [[Parametric_Modeling_%26_Simulation_Modes_in_EM.Cube#Running_Parametric_Sweep_Simulations_in_EM.Cube | Parametric Sweep]]| style="width:180px;" | Varies the value(s) of one or more project variables| style="width:150px;" | SBR| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires definition of sweep variables, works only with SBR solver as the physical scene may change during the sweep |-| style="width:120px;" | [[#Transmitter_Sweep | Transmitter Sweep]]| style="width:180px;" | Activates two or more transmitters sequentially with only one transmitter broadcasting at each simulation run | style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires at least two transmitters in the scene, works only with Polarimatrix solver and requires an existing ray database|-| style="width:120px;" | [[#Rotational_Sweep | Rotational Sweep]]| style="width:180px;" | Rotates the radiation pattern of the transmit antenna(s) sequentially to model beam steering | style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Works only with Polarimatrix solver and requires an existing ray database|-| style="width:120px;" | [[#Mobile_Sweep | Mobile Sweep]]| style="width:180px;" | Considers one pair of active transmitter and receiver at each simulation run to model a mobile communication link| style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires the same number of transmitters and receivers, works only with Polarimatrix solver and requires an existing ray database|}
Besides visualizing the coverage map and received rays in the [[EM.Cube|EM.CUBE]]'s [[Propagation Module]], you can also plot the '''Path Loss''' of all the receivers belonging to a receiver set as well as the '''Power Delay Profile''' of individual receivers. To plot these data, go the '''Observables''' section of the Navigation Tree and right click Click on the '''Receivers''' each item. From in the context menu, select '''Plot Path Loss''' or '''Plot Power Delay Profile''', respectively. The path loss data between the active transmitter and all the receivers belonging above list to a receiver set are plotted on a Cartesian graph. The horizontal axis of this graph represents the index of the receiver. Power Delay Profile is a bar chart that plots the power of individual rays received by the currently selected receiver versus their time delay. If there is a line of sight (LOS) between a transmitter and receiver, the LOS ray will have the smallest delay and therefore will appear first in the bar chart. Sometimes you may have several rays arriving at a receiver at the same time, i.e. all with the same delay, but with different power level. These will appear as stacked bars in the chartlearn more about each simulation mode.
You can also plot set the path loss and power delay profile graphs and many others from [[EM.Cube|simulation mode in EM.CUBE]]Terrano's data manager. You can open data manager by clicking simulation run dialog using the drop-down list labeled '''Data ManagerSimulation Mode''' [[File:data_manager_icon.png]] button of the '''Compute Toolbar''' or by selecting '''Compute [[File:larrow_tnA single-frequency analysis is a single-run simulation.png]] Data Manager''' from All the menu bar or by right clicking on other simulation modes in the '''Data Manager''' item of the Navigation Tree and selecting Open Data Manager... from the contextual menu or by using the keyboard shortcut '''Ctrl+D'''above list are considered multi-run simulations. In the Data manager Dialogmulti-run simulation modes, you will see certain parameters are varied and a list collection of all the simulation data files available for plottingare generated. These include At the theta and phi angles of arrival and departure end of a sweep simulation, you can plot the selected receiver. You output parameter results on 2D graphs or you can select any animate the 3D simulation data file by clicking and highlighting its '''ID''' in from the table and then clicking the '''Plot''' buttonnavigation tree.
=== Output Data Files ==={{Note| EM.Terrano's frequency sweep simulations are very fast because the geometrical optics (ray tracing) part of the simulation is frequency-independent.}}
At the end of an SBR simulation, the results are written into a main output data file with the reserved name of SBR_Results.RTOUT. This file has the following format:=== Transmitter Sweep ===
NEW LINE:When your propagation scene contains two or more transmitters, whether they all belong to the same transmitter set with the same radiation pattern or to different transmitter sets, EM.Terrano assumes all to be coherent with respect to one another. In other words, synchronous transmitters are always assumed. The rays originating from all these transmitters are superposed coherently and vectorially at each receiver. In a transmitter sweep, on the other hand, EM.Terrano assumes only one transmitter broadcasting at a time. The result of the sweep simulation is a number of received power coverage maps, each corresponding to a transmitter in the scene.
* Receiver Number* Receiver Base X, Y , Z Coordinates* Receiver Height{{Note| EM.Terrano's transmitter sweep works only with the Polarimatrix Solver and requires an existing ray database previously generated using the Channel Analyzer.}}
NEW LINE:=== Rotational Sweep ===
Number You can rotate the 3D radiation patterns of Raysboth the transmitters and receivers from the property dialog of the parent transmitter set or receiver set. This is done in advance before a SBR simulation starts. You can define one or more of the rotation angles of a transmitter set or a receiver set as sweep variables and perform a parametric sweep simulation. In that case, the entire scene and all of its buildings are discretized at each simulation run and a complete physical SBR ray tracing simulation is carried out. However, we know that the polarimetric characteristics of the propagation channel are independent of the transmitter or receiver antenna patterns or their rotation angles. A rotational sweep allows you to rotate the radiation pattern of the transmitter(s) about one of the three principal axes sequentially. This is equivalent to the steering of the beam of the transmit antenna either mechanically or electronically. The result of the sweep simulation is a number of received power coverage maps, each corresponding to one of the angular samples. To run a rotational sweep, you must specify the rotation angle.
NEW LINE:{{Note| EM.Terrano's rotational sweep works only with the Polarimatrix Solver and requires an existing ray database previously generated using the Channel Analyzer.}}
=== Mobile Sweep === In a mobile sweep, each transmitter is paired with a receiver according to their indices in their parent sets. At each simulation run, only one (Tx, Rx) pair is considered to be active in the scene. As a result, the generated coverage map takes a different meaning implying the sequential movement of the transmitter and receiver pair along their corresponding paths. In other words, the set of point transmitters and the set of point receivers indeed represent the locations of a single transmitter and a single receiver at different instants of time. It is obvious that the total number of transmitters and total number of receivers in the scene must be equal. Otherwise, EM.Terrano will prompt an error message. [[EM.Cube]] provides a '''Mobile Path Wizard''' that facilitates the creation of a transmitter set or a receiver set along a specified path. This path can be an existing nodal curve (polyline or NURBS curve) or an existing line objects. You can also import a sptial Cartesian data file containing the coordinates of the base location points. For more information, refer to [[Glossary_of_EM.Cube%27s_Wizards#Mobile_Path_Wizard | Mobile Path Wizard]]. {{Note| EM.Terrano's mobile sweep works only with the Polarimatrix Solver and requires an existing ray database previously generated using the Channel Analyzer.}} === Investigating Propagation Effects Selectively One at a Time === In a typical SBR ray tracing simulation, EM.Terrano includes all the propagation effects such as direct (LOS) rays, ray reflection and transmission, and edge diffractions. At the end of a SBR simulation, you can visualize the received power coverage map of your propagation scene, which appears under the receiver set item in the navigation tree. The figure below shows the received power coverage map of the random city scene with a vertically polarized half-wave dipole transmitter located 10m above the ground and a large grid of vertically polarized half-wave dipole receivers placed 1.5m above the ground. The legend box shows the limits of the color map between -23dBm as the maximum and -150dB (the default receiver sensitivity value) as the minimum.  <table><tr><td> [[Image:UrbanCanyon10.png|thumb|left|640px|The received power coverage map of the random city scene with a dipole transmitter.]] </td></tr></table> Sometime it is helpful to change the scale of the color map to better understand the dynamic range of the coverage map. If you double-click on the legend or right-click on the coverage map's name in the navigation tree and select '''Properties''', the Plot Settings dialog opens up. Select the '''User-Defined''' item and set the lower and upper bounds of color map as you wish. <table><tr><td> [[Image:UrbanCanyon15.png|thumb|left|480px|The plot settings dialog of the coverage map.]] </td></tr></table><table><tr><td> [[Image:UrbanCanyon16.png|thumb|left|640px|The received power coverage map of the random city scene with a user-defined color map scale between -80dBm and -20dBm.]] </td></tr></table> To better understand the various propagation effects, EM.Terrano allows you to enable or disable these effects selectively. This is done from the Ray Tracing Simulation Engine Settings dialog using the provided check boxes.  <table><tr><td> [[Image:UrbanCanyon14.png|thumb|left|640px|EM.Terrano's simulation run dialog showing the check boxes for controlling various propagation effects.]] </td></tr></table> <table><tr><td> [[Image:UrbanCanyon11.png|thumb|left|640px|The received power coverage map of the random city scene with direct LOS rays only.]] </td></tr><tr><td> [[Image:UrbanCanyon12.png|thumb|left|640px|The received power coverage map of the random city scene with reflected rays only.]] </td></tr><tr><td> [[Image:UrbanCanyon13.png|thumb|left|640px|The received power coverage map of the random city scene with diffracted rays only.]] </td></tr></table> == Working with EM.Terrano's Simulation Data == === The Ray Tracing Solvers' Output Simulation Data === Both the SBR solver and the Polarimatrix solver perform the same type of simulation but in two different ways. The SBR solver discretizes the scene including all the buildings and terrain, shoots a large number of rays from the transmitters and collects the rays at the receivers. The Polarimatrix solver does the same thing using an existing polarimetric ray database that has been previously generated using EM.Terrano's Channel Analyzer. It incorporates the effects of the radiation patterns of the transmit and receive antennas in conjunction with the polarimetric channel characteristics. At the end of a ray tracing simulation, all the polarimetric rays emanating from the transmitter(s) or other sources that are received by the individual receivers are computed, collected, sorted and saved into ASCII data files. From the ray data, the total electric field at the location of receivers as well as the total received power are computed. The individual ray data include the field components of each ray, the ray's elevation and azimuth angles of departure and arrival (departure from the transmitter location and arrival at the receiver location), and time delay of the received ray with respect to the transmitter. If you specify the temperatures, noise figure and transmission line losses in the definition of the receiver sets, the noise power level and signal-to-noise ratio (SNR) at each receiver are also calculated, and so are the E<sub>b</sub>/N<sub>0</sub> and bit error rate (BER) for the selected digital modulation scheme. === Visualizing Field & Received Power Coverage Maps === In wireless propagation modeling for communication system applications, the received power at the receiver location is more important than the field distributions. In order to compute the received power, you need three pieces of information: * '''Total Transmitted Power (EIRP)''': This requires knowledge of the baseband signal power, the transmitter chain parameters, the transmission characteristics of the transmission line connecting the transmitter circuit to the transmitting antenna and the radiation characteristics of the transmitting antenna.* '''Channel Path Loss''': This is computed through SBR simulation. * '''Receiver Properties''': This includes the radiation characteristics of the receiving antenna, the transmission characteristics of the transmission line connecting the receiving antenna to the receiver circuit and the receiver chain parameters. In a simple link scenario, the received power P<sub>r</sub> in dBm is found from the following equation: <math> P_r [dBm] = P_t [dBm] + G_{TC} + G_{TA} - PL + G_{RA} + G_{RC} </math> where P<sub>t</sub> is the baseband signal power in dBm at the transmitter, G<sub>TC</sub> and G<sub>RC</sub> are the total transmitter and receiver chain gains in dB, respectively, G<sub>TA</sub> and G<sub>RA</sub> are the total transmitting and receiving antenna gains in dB, respectively, and PL is the channel path loss in dB. Keep in mind that EM.Terrano is fully polarimetric. The transmitting and receiving antenna characteristics are specified through the imported radiation pattern files, which are part of the definition of the transmitters and receivers. In particular, the polarization mismatch losses are taken into account through the polarimetric SBR ray tracing analysis.  If you specify the noise-related parameters of your receiver set, the signal-to-noise ratios (SNR) is calculated at each receiver location: SNR = P<sub>r</sub> - P<sub>n</sub>, where P<sub>n</sub> is the noise power level in dB. When planning, designing and deploying a communication system between points A and B, the link is considered to be closes and a connection established if the received signal power at the location of the receiver is above the noise power level by a certain threshold. In other words, the SNR at the receiver must be greater than a certain specified minimum SNR level. You specify (SNR)<sub>min</sub> ss part of the definition of receiver chain in the Receiver Set dialog. In the "Visualization Options" section of this dialog, you can also check the check box labeled '''Generate Connectivity Map'''. This is a binary-level black-and-white map that displays connected receivers in white and disconnected receivers in black. At the end of an SBR simulation, the computed SNR is displayed in the Receiver Set dialog for the selected receiver. The connectivity map is generated and added to the navigation tree underneath the received power coverage map node.  At the end of an SBR simulation, you can visualize the field maps and receiver power coverage map of your receiver sets. A coverage map shows the total '''Received Power''' by each of the receivers and is visualized as a color-coded intensity plot. Under each receiver set node in the navigation tree, a total of seven field maps together with a received power coverage map are added. The field maps include amplitude and phase plots for the three X, Y, Z field components plus a total electric field plot. To display a field or coverage map, simply click on its entry in the navigation tree. The 3D plot appears in the Main Window overlaid on your propagation scene. A legend box on the right shows the color scale and units (dB). The 3D coverage maps are displayed as horizontal confetti above the receivers. You can change the appearance of the receivers and maps from the property dialog of the receiver set. You can further customize the settings of the 3D field and coverage plots.  <table><tr><td>[[Image:AnnArbor Scene1.png|thumb|left|640px|The downtown Ann Arbor propagation scene.]]</td></tr><tr><td>[[Image:AnnArbor Scene2.png|thumb|left|640px|The electric field distribution map of the Ann Arbor scene with vertical dipole transmitter and receivers.]]</td></tr><tr><td>[[Image:AnnArbor Scene3.png|thumb|left|640px|The received power coverage map of the Ann Arbor scene with vertical dipole transmitter and receivers.]]</td></tr><tr><td>[[Image:AnnArbor Scene4.png|thumb|left| 640px |The connectivity map of the Ann Arbor scene with SNR<sub>min</sub> = 3dB with the basic color map option.]]</td></tr><tr><td>[[Image:AnnArbor Scene5.png|thumb|left| 640px |The connectivity map of the Ann Arbor scene with SNR<sub>min</sub> = 20dB with the basic color map option.]]</td></tr></table> === Visualizing the Rays in the Scene === At the end of a SBR simulation, each receiver receives a number of rays. Some receivers may not receive any rays at all. You can visualize all the rays received by a certain receiver from the active transmitter of the scene. To do this, right click the '''Receivers''' item of the Navigation Tree. From the context menu select '''Show Received Rays'''. All the rays received by the currently selected receiver of the scene are displayed in the scene. The rays are identified by labels, are ordered by their power and have different colors for better visualization. You can display the rays for only one receiver at a time. The receiver set property dialog has a list of all the individual receivers belonging to that set. To display the rays received by another receiver, you have to change the '''Selected Receiver''' in the receiver set's property dialog. If you keep the mouse focus on this dropdown list and roll your mouse scroll wheel, you can scan the selected receivers and move the rays from one receiver to the next in the list. To remove the visualized rays from the scene, right click the Receivers item of the Navigation Tree again and from the context menu select '''Hide Received Rays'''. You can also view the ray parameters by opening the property dialog of a receiver set. By default, the first receiver of the set is always selected. You can select any other receiver from the drop-down list labeled '''Selected Receiver'''. If you click the button labeled '''Show Ray NumberData''', a new dialog opens up with a table that contains all the received rays at the selected receiver and their parameters: * Delay is the total time delay that a ray experiences travelling from the transmitter to the receiver after all the reflections, transmissions and diffractions and is expressed in nanoseconds.* Ray Field is the received electric field at the receiver location due to a specific ray and is given in dBV/m.* Ray Power is the received power at the receiver due to a specific ray and is given in dBm.* Angles of Arrival are the θ and φ angles of the incoming ray at the local spherical coordinate system of the receiver. <table><tr><td> [[Image:UrbanCanyon17.png|thumb|left|720px|EM.Terrano's ray data dialog showing a selected ray.]] </td></tr></table> The Ray Data Dialog also shows the '''Total Received Power''' in dBm and '''Total Received Field''' in dBV/m due to all the rays received by the receiver. You can sort the rays based on their delay, field, power, etc. To do so, simply click on the grey column label in the table to sort the rays in ascending order based on the selected parameter. You can also select any ray by clicking on its '''ID''' and highlighting its row in the table. In that case, the selected rays is highlighted in the Project Workspace and all the other rays become thin (faded). {{Note|All the received rays are summed up coherently in a vectorial manner at the receiver location.}} <table><tr><td> [[Image:UrbanCanyon18.png|thumb|left|640px|Visualization of received rays at the location of a selected receiver in the random city scene.]] </td></tr></table> === The Standard Output Data File === At the end of an SBR simulation, EM.Terrano writes a number of ASCII data files to your project folder. The main output data file is called "sbr_results.RTOUT". This file contains all the information about individual receivers and the parameters of each ray that is received by each individual receiver. At the end of an SBR simulation, the results are written into a main output data file with the reserved name of SBR_Results.RTOUT. This file has the following format: Each receiver line has the following information: * Receiver ID* Receiver X, Y, Z coordinates* Total received power in dBm* Total number of received rays Each rays line received by a receiver has the following information: * Ray Index* Delay in nsec
* θ and φ Angles of Arrival in deg
* θ and φ Angles of Departure in deg
* Delay in nsec* Real(and imaginary parts of the three E<supsub>Vx</supsub>) & Imag(, E<sup>V</sup>)* Real(E<sup>H</sup>) & Imag(E<sup>H</sup>)* Real('''E.e<sub>Ry</sub>''') & Imag(''', E.e<sub>Rz</sub>''')components* Number of ray hit points * PowerCoordinates of individual hit points
The angles of arrival are the θ and φ angles of a received ray measured in degrees and are referenced in the local spherical coordinate systems centered at the location of the receiver. The angles of departure for a received ray are the θ and φ angles of the originating transmitter ray, measured in degrees and referenced in the local spherical coordinate systems centered at the location of the active transmitter, which eventually arrives at the receiver. The total time delay is measured in nanoseconds between t = 0 nsec at the time of launch from the transmitter location till being received at the receiver location. The last four columns show the real and imaginary parts of the received electric fields with vertical and horizontal polarizations, respectively. The complex field values are normalized in a way that when their magnitude is squared, it equals the received ray power. If the active transmitter is an isotropic radiator with either a vertical or horizontal polarization, then the field components corresponding to the other polarization will have zero entries in the output data file.
<table><tr><td> [[FileImage:prop_run8_tn.png|800pxthumb|left|720px|A typical SBR output data file.]]</td></tr></table>
Figure: A typical SBR output data file.=== Plotting Other Simulation Results ===
=== Running A Frequency Sweep With SBR ===Besides "sbr_results.out", [[EM.Terrano]] writes a number of other ASCII data files to your project folder. You can view or plot these data in [[EM.Cube]]'s Data Manager. You can open data manager by clicking the '''Data Manager''' [[File:data_manager_icon.png]] button of the '''Simulate Toolbar''' or by selecting '''Menu > Simulate > Data Manager''' from the menu bar or by right-clicking on the '''Data Manager''' item of the navigation tree and selecting '''Open Data Manager...''' from the contextual menu or by using the keyboard shortcut {{key|Ctrl+D}}.
By default, you run a single-frequency simulation The available data files in [[EM.Cube|EM.CUBE]]'s [[Propagation Module]]. You set the operational frequency "2D Data Files" tab of a SBR simulation in the project's '''Frequency Dialog''', which can be accessed in a number of waysData Manger include:
# By clicking the * '''FrequencyPath Loss''' [[File:freq_iconThe channel path loss is defined as PL = P<sub>r</sub> - EIRP.png]] button The path loss data are stored in a file called "SBR_receiver_set_name_PATHLOSS.DAT" as a function of the '''Compute Toolbar'''receiver index. The path loss data make sense only if your receiver set has the default isotropic radiator.# By selecting * '''ComputePower Delay Profile''' [[File:larrow_tnThe delays of the individual rays received by the selected receiver with respect to the transmitter are expressed in ns and tabulated together with the power of each ray in the file "SBR_receiver_set_name_DELAY.png]]'''Frequency SettingsDAT"...''' You can plot these data from the Menu BarData Manager as a bar chart called the power delay profile.# Using The bars indeed correspond to the keyboard shortcut difference between the ray power in dBm and the minimum power threshold level in dBm, which makes them a positive quantity. * '''Ctrl+FAngles of Arrival'''.# By double clicking : These are the frequency section (box) Theta and Phi angles of the '''Status Bar'''individual rays received by the selected receiver and saved to the files "SBR_receiver_set_name_ThetaARRIVAL.<br /> ANG" and "SBR_receiver_set_name_PhiARRIVAL.ANG". You can plot them in the Data Manager in polar stem charts.
When you run a frequency or parametric sweep in [[File:prop_freqEM.pngTerrano]] , a tremendous amount of data may be generated. [[File:prop_run10EM.pngTerrano]]only stores the '''Received Power''', '''Path Loss''' and '''SNR''' of the selected receiverin ASCII data files called "PREC_i.DAT", "PL_i.DAT" and "SNR_i.DAT", where is the index of the receiver set in your scene. These quantities are tabulated vs. the sweep variable's samples. You can plot these files in EM.Grid.
(Left) Project[[Image:Info_icon.png|40px]] Click here to learn more about working with data filed and plotting graphs in [[EM.Cube]]'s frequency dialog and (Right) the frequency settings dialog'''[[Defining_Project_Observables_%26_Visualizing_Output_Data#The_Data_Manager | Data Manager]]'''.
You can also select the '''Frequency Sweep''' option in the '''Simulation Mode''' drop-down list of the '''Run Dialog'''<table><tr><td> [[Image:Terrano pathloss. Click the '''Settings...''' button on the right side of this dropdown list to open up the Frequency Settings Dialog. Based on the original values png|thumb|360px|Cartesian graph of the project center frequency and bandwidth, the '''Start Frequency''' and '''End Frequency''' have default valuespath loss. You can also change the '''Number of Samples'''. Once you click the '''Run''' button, ]] </td><td> [[EMImage:Terrano delay.Cubepng|EMthumb|360px|Bar graph of power delay profile.CUBE]] performs a frequency sweep by assigning each of the frequency samples as the current operational frequency and running the SBR simulation engine at that frequency</td></tr><tr><td> [[Image:Terrano ARR phi. All the simulation data at all frequency samples are saved into the output data files including "SBR_results.RTOUT". After the completion png|thumb|360px|Polar stem graph of a frequency sweep simulation, as many coverage maps as the number Phi angle of frequency samples are generated and added to the Navigation Tree under the Receiver Set's entryarrival. You can click on each of the coverage maps corresponding to each of the frequency samples and visualize it in the project workspace. You can also animate the coverage maps. To do so, right click on the receiver set's name in the Navigation Tree and select ''']] </td><td> [[Animation]]''' from the contextual menuImage:Terrano ARR theta. The coverage maps start to animate by their order on the Navigation Tree. Once the entire list is displayed sequentially, it starts all over again from the beginning png|thumb|360px|Polar stem graph of the listTheta angle of arrival. During the [[animation]], the '''</td></tr><tr><td> [[Animation]] Controls''' dialog appears at the lower right corner of the screenImage:Terrano DEP phi. This dialog has a number png|thumb|360px|Polar stem graph of buttons for pause/resume, step forward/backward, and step to the end/start. The title Phi angle of each coverage map is shown in the box labeled '''Sample''' as it is displayed in the main windowdeparture. You can also change the speed of [[animation]]</td><td> [[Image:Terrano DEP theta. The default frame duration has a value png|thumb|360px|Polar stem graph of 300 (3x100) millisecondsTheta angle of departure. To stop the [[animation]], simply press the keyboard's '''Esc Key'''.</td></tr></table>
[[File:prop_run13.png]] [[File:prop_run14.png]]=== Visualizing 3D Radiation Patterns of Transmit and Receive Antennas in the Scene ===
Multiple coverage maps on When you designate a "User Defined Antenna Pattern" as the Navigation Tree radiator type of a transmitter set or a receiver set, EM.Terrano copies the imported radiation pattern data file from its original folder to the current project folder. The name of the ".RAD" file is listed under the '''3D Data Files''' tab of the data manager. Sometimes it might be desired to visualize these radiation patterns in your propagation scene at the end actual location of the transmitter or receiver. To do so, you have to define a frequency sweep new '''Radiation Pattern''' observable in the navigation tree. The label of the new observable must be identical to the name of the ".RAD" data file. In addition, the Theta and starting an [[animation]] from Phi angle increments of the new radiation pattern observable (expressed in degrees) must be identical to the Theta and Phi angular resolutions of the imported pattern file. If all these conditions are met, then go to the '''Simulate Menu''' and select the item '''Update All 3D Visualization'''. The contents of the 3D radiation patterns are added to the navigation tree. Click on one of the radiation pattern items in the navigation tree and it will be displayed in the contextual menuscene.
<table><tr><td>[[FileImage:prop_run15_tnUrbanCanyon6.png|thumb|left|640px|The received power coverage map of the random city scene with a highly directional dipole array transmitter.]]</td></tr></table>
By Default, [[AnimationEM.Cube]] controls always visualizes the 3D radiation patterns at the origin of coordinates, i.e. at (0, 0, 0). This is because that radiation pattern data are computed in the standard spherical coordinate system centered at (0, 0, 0). The theta and phi components of the far-zone electric fields are defined with respect to the X, Y and Z axes of this system. When visualizing the 3D radiation pattern data in a propagation scene, it is more intuitive to display the pattern at the location of the transmitter or receiver. The Radiation Pattern dialog allows you to translate the pattern visualization to any arbitrary point in the project workspace. It also allows you to scale up or scale down the pattern visualization with respect to the background scene.
=== Running In the example shown above, the imported pattern data file is called "Dipole_Array1.RAD". Therefore, the label of the radiation pattern observable is chosen to be "Dipole_Array1". The theta and phi angle increments are both 1° in this case. The radiation pattern has been elevated by 10m to be positioned at the location of the transmitter and a Parametric Sweep with SBR ===scaling factor of 0.3 has been used.
<table><tr><td>[[FileImage:prop_run24UrbanCanyon8.png|thumb|300pxleft|EM.CUBE's variable 640px|Setting the pattern parameters in the radiation pattern dialog.]]</td></tr></table><table><tr><td>[[Image:UrbanCanyon7.png|thumb|left|720px|Visualization of the 3D radiation pattern of the directional transmitter in the random city scene.]]</td></tr></table>
[[File:prop_run23There is an important catch to remember here.png|thumb|250px|Dialog When you define a radiation pattern observable for defining your project, EM.Terrano will attempt to compute the overall effective radiation pattern of the entire physical structure. However, in this case, you defined the radiation pattern observable merely for visualization purposes. To stop EM.Terrano from computing the actual radiation pattern of your entire scene, there is a check box in EM.Terrano's Ray Tracer Simulation Engine Settings dialog that is labeled '''Do not compute new variables]]radiation patterns'''. This box is checked by default, which means the actual radiation pattern of your entire scene will not be computed automatically. But you need to remember to uncheck this box if you ever need to compute a new radiation pattern using EM.Terrano's SBR solver as an asymptotic EM solver (see next section).
In <table><tr><td>[[EMImage:UrbanCanyon9.Cubepng|thumb|left|640px|EM.CUBE]], all the CAD object properties as well as certain source, material and mesh [[parameters]] can be assigned as [[variables]]Terrano's Run Simulation dialog. [[Variables]] are defined to control and vary the values of such [[parameters]] either for editing purposes or to run parametric sweep or [[optimization]]. Variable are defined using the '''[[Variables]] Dialog''', which can be accessed in the three ways:</td></tr></table>
# By clicking the '''[[Variables]]''' [[File:variable_icon.png]] button of the '''Compute Toolbar'''.# By selecting '''Compute''' [[File:larrow_tn.png]] '''[[Variables]]...''' from the Menu Bar.# == Using the keyboard shortcut '''Ctrl+B'''EM.Terrano as an Asymptotic Field Solver ==
The [[variables]] dialog is initially emptyLike every other electromagnetic solver, EM. To add a new variable, click the Terrano'''Add''' button to open up the '''Add Variable/Syntax Dialog'''. In this dialog you have to type in a name s SBR ray tracer requires an excitation source and one or more observables for the new variable and choose a typegeneration of simulation data. The default type is '''Uniformly Spaced Samples'''EM. You also need to specify the '''Start''', '''Stop''' Terrano offers several types of sources and '''Step''' values observables for the variablea SBR simulation. In You already learned about the figure below, transmitter set as a variable called "Tx_Height" is defined that varies between 2 source and 10 with equal steps of 2. This means the sample receiver set {2,4,6,8,10}. When you return to the [[variables]] dialog, the syntax of the new variable is shown as 2:10:2an observable. The last number in this syntax is always You can mix and match different source types and observable types depending on the variable step. In this example, this variable is going to be used to control the height requirements of the transmitter in a propagation sceneyour modeling problem.
Next, you have to attach the variable to the CAD object. In this case, the CAD object is the point object that represents the transmitter's radiator. To attach a variable to a CAD object, open the object's property dialog and type The available source types in the name of the variable as the value of a property or parameterEM. In this case, the variable Tx_Height is going to control the Z-Coordinate of the point object. Once the value of the object parameter is replaced by the name of an already defined variable, it is updated with the current value of that variable. In the case of a variable of "Uniformly Spaced Samples" type, the current value is the start value. This value will be incrementally varied during a parametric sweep simulation process. Note that a variable can take a fixed value or a discrete set of values, too. You can always open the [[variables]] dialog and change the value or syntax of any variable. To make a new or modified value effective, click the '''Apply''' button of the [[variables]] dialog. You can test the values by performing a '''Dry Run''' of the selected variable. This runs an [[animation]] of the project workspace as the value of the variable changes and all the related CAD objects Terrano are updated accordingly. Note that you can attach the same variable to more than one CAD object property or to the properties of different objects. You can also define multiple values or syntaxes to the same variable. To do so, open the '''Add Variable/Syntax Dialog''', and instead of typing in a new variable name, choose an existing variable name from the '''Name''' dropdown list. This will add a new value or syntax to the existing syntax(es) of the selected variable. When you return to the [[variables]] dialog, [[variables]] with more than one value or syntax will have a dropdown list in the '''Syntax''' column. You can choose any of these values or syntaxed at any time and make the change effective by clicking the '''Apply''' button.:
{| class="wikitable"|-! scope="col"| Icon! scope="col"| Source Type! scope="col"| Applications! scope="col"| Restrictions|-| style="width:30px;" | [[File:prop_run25transmitter_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Point Transmitter Set | Point Transmitter Set]]| style="width:250px;" | Modeling realsitic antennas & link budget calculations| style="width:250px;" | Requires to be associated with a base location point set|-| style="width:30px;" | [[File:hertz_src_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Hertzian Short Dipole Source | Hertzian Short Dipole]]| style="width:250px;" | Almost omni-directional physical radiator| style="width:250px;" | None, stand-alone source|-| style="width:30px;" | [[File:huyg_src_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Huygens Source | Huygens Source]]| style="width:250px;" | Used for modeling equivalent sources imported from other [[EM.Cube]] modules | style="width:250px;" | None, stand-alone source imported from a Huygens surface data file|}
Replacing Click on each type to learn more about it in the value [[Glossary of a CAD object parameter with a variable nameEM.Cube's Materials, Sources, Devices & Other Physical Object Types]].
To run a parametric sweep, open the '''Run Dialog''' and select the '''Parametric Sweep''' option The available observables types in the '''Simulation Mode''' drop-down list. If you have not defined any [[variablesEM.Terrano]] in the project, the box in the '''are:Â {| class="wikitable"|-! scope="col"| Icon! scope="col"| Source Type! scope="col"| Applications! scope="col"| Restrictions|-| style="width:30px;" | [[VariablesFile:receiver_icon.png]]''' row before the '''View''' will be red| style="width:150px;" | [[Glossary of EM. You have Cube's Simulation Observables & Graph Types#Point Receiver Set | Point Receiver Set]]| style="width:250px;" | Generating received power coverage maps & link budget calculations| style="width:250px;" | Requires to turn it into green before you can run be associated with a simulation. By clicking the '''View''' button, you can open up the base location point set|-| style="width:30px;" | [[variablesFile:Distr Rx icon.png]] dialog from here. Once you click the '''Run''' button, | style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Distributed Receiver Set |EM.CUBEDistributed Receiver Set]] performs | style="width:250px;" | Computing received power at a parametric sweep receiver characterized by incrementally varying the values of all the defined Huygens surface data| style="width:250px;" | None, stand-alone source imported from a Huygens surface data file|-| style="width:30px;" | [[variablesFile:fieldsensor_icon.png]] from their start to stop values at the specified steps and updating all the related CAD objects. After the completion | style="width:150px;" | [[Glossary of a parametric sweep simulation, as many coverage maps as the total number of variable samples are generated and added to the Navigation Tree under the receiver setEM.Cube's entry. You can click on each of the coverage maps Simulation Observables & Graph Types#Near-Field Sensor Observable | Near-Field Sensor]]| style="width:250px;" | Generating electric and visualize it in the project workspace. You can also animate the coverage magnetic field distribution maps sequentially. To do so| style="width:250px;" | None, right click on the receiver set's name in the Navigation Tree and select '''stand-alone observable|-| style="width:30px;" | [[AnimationFile:farfield_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube''' from s Simulation Observables & Graph Types#Far-Field Radiation Pattern Observable | Far-Field Radiation Pattern]]| style="width:250px;" | Computing the contextual menu. To stop effective radiation pattern of a radiator in the presence of a large scattering scene | style="width:250px;" | None, stand-alone observable|-| style="width:30px;" | [[animationFile:huyg_surf_icon.png]], simply press the keyboard| style="width:150px;" | [[Glossary of EM.Cube's '''Esc Key'''Simulation Observables & Graph Types#Huygens Surface Observable | Huygens Surface]]| style="width:250px;" | Collecting tangential field data on a box to be used later as a Huygens source in other [[EM.Cube]] modules| style="width:250px;" | None, stand-alone observable|}
Click on each type to learn more about it in the [[File:prop_run26Glossary of EM.pngCube's Simulation Observables & Graph Types]]. When you define a far-field observable in EM.Terrano, a collection of invisible, isotropic receivers are placed on the surface of a large sphere that encircles your propagation scene and all of its geometric objects. These receivers are placed uniformly on the spherical surface at a spacing that is determined by your specified angular resolutions. In most cases, you need to define angular resolutions of at least 1° or smaller. Note that this is different than the transmitter rays' angular resolution. You may have a large number of transmitted rays but not enough receivers to compute the effective radiation pattern at all azimuth and elevation angles. Also keep in mind that with 1° Theta and Phi angle increments, you will have a total of 181 × 361 = 65,341 spherically placed receivers in your scene.
Choosing parametric sweep as the simulation mode in the run dialog. {{Note that one variable has been defined and | Computing radiation patterns using EM.Terrano's SBR solver typically takes much longer computation times than using [[EM.Cube|EM.CUBE]] is ready to run 's other computational modules.}} <table><tr><td> [[Image:SBR pattern.png|thumb|540px|Computed 3D radiation pattern of two vertical short dipole radiators placed 1m apart in the simulationfree space at 1GHz.]] </td></tr></table>
[[File:prop_run27_tn.png|800px]]== Statistical Analysis of Propagation Scene ==
EM.Terrano's coverage maps display the received power at the location of all the receivers. The receivers together from a set/ensemble, which might be uniformly spaced or distributed across the propagation scene or may consist of randomly scattered radiators. Every coverage map shows the '''Mean''' and '''Standard Deviation''' of the scene received power for all the receivers involved. These information are displayed at the end bottom of a parametric sweep where the sweep variable is the transmitter heightcoverage map's legend box and are expressed in dB.
=== Statistical Analysis When you run either a frequency sweep or a parametric sweep simulation in EM.Terrano, you have the option to generate two additional coverage maps: one for the mean of Propagation Scene ===all the individual sample coverage maps and another for their standard deviation. To do so, in the '''Run Dialog''', check the box labeled '''"Create Mean and Standard Deviation received power coverage maps"'''. Note that the mean and standard deviation values displayed on the individual coverage maps correspond to the spatial statistics of the receivers in the scene, while the mean and standard deviation coverage maps show the statistics with respect to the frequency or other sweep variable sets at each point in the site. Also, note that both of the mean and standard deviation coverage maps have their own spatial mean and standard deviation values expressed in dB at the bottom of their legend box.
<table><tr><td> [[EMImage:PROP MAN12.Cubepng|thumb|left|480px|EM.CUBE]]Terrano's coverage maps display simulation run dialog showing frequency sweep as the received power at the location of all the receiverssimulation mode along with statistical analysis. The receivers together from a set]] </ensemble, which might be uniformly spaced or distributed across the propagation scene or may consist of randomly scattered radiators. Every coverage map shows the '''Mean''' and '''Standard Deviation''' of the received power for all the receivers involved. These information are displayed at the bottom of the coverage map's legend box and are expressed in dB.td></tr></table>
In the <table><tr><td> [[Propagation Module]], when you ran a sweep simulation (frequency, transmitter or parametric), you also have the option to generate two additional coverage mapsImage: one for the mean of all the individual sample coverage maps and another for their standard deviationUrbanCanyon4. To do so, in the '''Run Dialog''', check the box labeled '''"Create Mean and Standard Deviation Coverage Maps"'''. Note that the png|thumb|left|640px|The mean and standard deviation values displayed on the individual coverage maps correspond to map at the spatial statistics end of the receivers in the scene, while the mean and standard deviation coverage maps correspond to a frequency, transmitter or variable sets defined for the sweep simulation. Also, note that both of the mean and ]] </td></tr><tr><td> [[Image:UrbanCanyon5.png|thumb|left|640px|The standard deviation coverage maps have their own spatial mean and standard deviation values expressed in dB map at the bottom end of their legend boxa frequency sweep.]] </td></tr></table>
[[File:prop_run21_tn.png]]<br />
The mean coverage map at the end of a transmitter sweep.<hr>
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The standard deviation coverage map at the end of a transmitter sweep[[Image:Tutorial_icon.png|30px]] '''[[EM.Cube#EM.Terrano_Documentation | EM.Terrano Tutorial Gateway]]'''
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