[[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.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 Primer Tutorial Gateway]]'''Â [[Image:Back_icon.png|30px]] '''[[EM.Cube | Back to EM.Cube Main Page]]'''==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.
{{Note|Since its introduction in 2002, EM.Terrano is 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 '''[[Propagation Module]]''' of '''[[EMsimulator finds the dominant propagation paths at each specific physical site.Cube]]''', It calculates the true signal characteristics at the actual locations using physical databases of the buildings and terrain at a comprehensivegiven site, integrated, modular electromagnetic modeling not those of a statistically average or representative environment. The earlier versions of EM.Teranno shares Terrano's SBR solver relied on certain assumptions and approximations such as the visual interfacevertical 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 parametric CAD modeler, data visualization toolsyou 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-d tree algorithms borrowed from the field of computer graphics and many more utilities video gaming to achieve the ultimate speed and features collectively known as '''[[CubeCAD]]''' with all of [[EM.Cube]]'s other computational modulesefficiency in geometrical optics ray tracing.}}
[[Image:MOREInfo_icon.png|40px30px]] Click here to learn more about the '''[[Getting_Started_with_EM.CUBE Basic Principles of SBR Ray Tracing | EM.Cube Modeling EnvironmentBasic SBR Theory]]'''.
<table><tr><td> [[Image:MOREManhattan1.png|40pxthumb|left|420px|A large urban propagation scene featuring lower Manhattan.]] Click here to learn more about the basic functionality of '''[[CubeCAD]]'''.</td></tr></table>
=== The Importance of Physics-Based Site-Specific EM.Terrano as the Propagation ModelingModule of EM.Cube ===
Every wireless communication system involves a transmitter that transmits some sort EM.Terrano is the ray tracing '''Propagation Module''' of signal (voice, video, data, etc'''[[EM.)Cube]]''', a receiver that receives and detects the transmitted signalcomprehensive, integrated, 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 receiver. The channel is the physical medium in which the modular electromagnetic waves propagatemodeling environment. The successful design of a communication system depends on an accurate link budget analysis that determines whether the receiver receives adequate signal power to detect it against the background noiseEM. The simplest channel is Terrano shares the free space. Real communication channelsvisual interface, however3D parametric CAD modeler, are data visualization tools, and many more complicated utilities and involve a large number features collectively known as [[Building_Geometrical_Constructions_in_CubeCAD | CubeCAD]] with all of wave scatterers[[EM. 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 anglesCube]]'s other computational modules.
The rapid growth With the seamless integration of wireless communications along 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 high costs associated with the design and deployment two ends of effective wireless infrastructures underline your propagation channel. Conversely, you can analyze a persistent need for computer aided communication network planning toolspropagation scene in EM. The different Terrano, collect all the rays arriving received at a certain receiver location create constructive and destructive interference patterns. This is known import them as the multipath effect. This together with the shadowing effects caused by building obstructions lead coherent plane wave sources to channel fading[[EM. The use of statistical models for prediction of fading effects is widely popular among communication system designersTempo]], [[EM. These models are either based on measurement data Libera]], [[EM.Picasso]] or derived from simplistic analytical frameworks[[EM. 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 detailsIllumina]].
=== Line-of-Sight vs[[Image:Info_icon.png|30px]] Click here to learn more about '''[[Getting_Started_with_EM.Cube | EM.Cube Modeling Environment]]'''. Multipath Propagation Channel ===
In a free-space line-=== Advantages & Limitations of-sight (LOS) communication system, the signal propagates directly from the transmitter to the receiver without encountering any obstacles (scatterers). Free-space line-of-sight channels are ideal scenarios that can typically be used to model aerial or space communication system applicationsEM.Terrano's SBR Solver ===
[[Image:MOREEM.png|40px]] Click here to learn more about Terrano's SBR simulation engine utilizes an intelligent ray tracing algorithm that is based on the theory concept of k-dimensional trees. A k-d tree is a '''[[Freespace-Space Propagation Channel]]'''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.
[[Image:multi1_tnEM.png|thumb|500px|A multipath propagation scene showing Terrano performs fully polarimetric and coherent SBR simulations with arbitrary transmitter antenna patterns. Its SBR simulation engine is a true asymptotic "field" solver. The amplitudes and phases of all the rays arriving at a particular receiver.]]In ground-based systemsthree vectorial field components are computed, analyzed and preserved throughout the presence of entire ray tracing process from the ground as a very large reflecting surface affects the signal propagation source location to a large extentthe field observation points. Along You can visualize the path from a transmitter to a receiver, magnitude and phase of all six electric and magnetic field components at any point in the signal may also encounter many obstacles and scatterers such as buildings, vegetation, etccomputational domain. In an urban canyon environment with many most scenes, the buildings of different heights and other scatterers, a line of sight between the transmitter and receiver ground or terrain can hardly be establishedassumed to be made of homogeneous materials. These are represented by their electrical properties such as permittivity ε<sub>r</sub> and electric conductivity σ. More complex scenes may involve a multilayer ground or multilayer building walls. In such cases, one can no longer use the propagating signals bounce back and forth among the building surfaces. It is these reflected simple reflection or diffracted signals that are often received and detected by the receivertransmission coefficient formulas for homogeneous medium interfaces. Such environments are referred to as âmultipathâEM. The group Terrano calculates the reflection and transmission coefficients of rays arriving at a specific receiver location experience different attenuations multilayer structures as functions of incident angle, frequency and different time delays. This gives rise to constructive polarization and destructive interference patterns that cause fast fading. As a receiver moves locally, uses them at the receiver power level fluctuates sizably due to these fading effectsrespective specular points.
Link budget analysis for a multipath channel It is a challenging task due very important to the large size of the computational domains involved. Typical propagation scenes usually involve length scales keep in mind that SBR is an asymptotic electromagnetic analysis technique that is based on Geometrical Optics (GO) and the order Uniform Theory of thousands of wavelengthsDiffraction (UTD). To calculate the path loss between the transmitter and receiverIt is not a "full-wave" technique, one must solve [[Maxwell's Equations|and it does not provide a direct numerical solution of Maxwell's equations]] in an extremely large space. Full-wave numerical techniques like the Finite Difference Time Domain (FDTD) method, which require SBR makes a fine discretization number of assumptions, chief among them, a very high operational frequency such that the computational domainlength 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 therefore impractical based on far field approximations. In order to maintain a high computational speed for solving large-scale urban propagation problems, EM. The practical solution is Terrano ignores double diffractions. Diffractions from edges give rise to use asymptotic techniques such as SBR, which utilize analytical techniques over a large distances rather than a brute force discretization number of the entire computational domainnew secondary rays. Such asymptotic techniques, The power of coursediffracted rays drops much faster than reflected rays. In other words, have to compromise modeling accuracy for computational efficiencyan 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.
=== The SBR Method ===<table><tr><td> [[Image:Multipath_Rays.png|thumb|left|500px|A multipath urban propagation scene showing all the rays collected by a receiver.]]</td></tr></table>
== EM.Terrano provides an asymptotic ray tracing simulation engine that is based on Features at 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 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 source. 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 requirements.Glance ==
When a ray hits an obstructing surface, one or more of the following phenomena may happen:=== Scene Definition / Construction ===
# Reflection from the locally flat <ul> <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 volume 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 surfaces with arbitrary geometries and material properties and random rough surfaceprofiles</li># Transmission through <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 locally flat surfaceprincipal axes</li># Diffraction <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 an edge between two conjoined locally flat surfacesother 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></ul>
[[Image:MORE.png|40px]] Click here to learn more about the theory of '''[[SBR Method]]'''.=== Wave Propagation Modeling ===
=== A Note on <ul> <li> Fully 3D polarimetric and coherent Shoot-and-Bounce-Rays (SBR) simulation engine</li> <li> GTD/UTD diffraction models for diffraction from building edges and terrain</li> <li> Triangular surface mesh generator for discretization of 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 Pros calculation of E<sub>b</sub>/N<sub>0</sub> and Cons Bit error rate (BER)</li> <li> Incredibly fast frequency sweeps of EM.Terrano's the entire propagation scene in a single SBR Solver ===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>
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. === Data Generation & Visualization ===
EM.Terrano performs fully polarimetric <ul> <li> Standard output parameters for received power, path loss, SNR, E<sub>b</sub>/N<sub>0</sub> and coherent SBR simulations with arbitrary transmitter antenna patterns. Its SBR simulation engine is a true asymptotic "field" solver. The amplitudes and phases BER at each individual receiver</li> <li> Graphical visualization of all propagating rays in the three vectorial field components are computed, analyzed scene</li> <li> Received power coverage maps</li> <li> Link connectivity maps (based on minimum required SNR and preserved throughout the entire ray tracing process from the source location to the field observation points. You can visualize the magnitude and phase BER)</li> <li> Color-coded intensity plots of all six polarimetric electric and magnetic field components distributions</li> <li> Incoming ray data analysis at any point in the computational domain. In most sceneseach receiver including delay, the buildings angles of arrival and the ground or terrain can be assumed to be made of homogeneous materials. These are represented by their electrical properties such as permittivity εdeparture<sub/li>r <li> Cartesian plots of path loss along defined paths</subli> and electric conductivity σ. More complex scenes may involve a multilayer ground or multilayer building walls. In such cases, one can no longer use <li> Power delay profile of the simple reflection or transmission coefficient formulas for homogeneous medium interfaces. EM.Terrano calculates the reflection and transmission coefficients selected receiver</li> <li> Polar stem charts of multilayer structures as functions angles of incident angle, frequency arrival and polarization and uses them at departure of the respective specular points. selected receiver</li></ul>
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 == Building a "full-wave" technique, and it does not provide a direct numerical solution of [[Maxwell's Equations|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 Propagation Scene 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.==
[[Image:PROP14(1).png|thumb|250px|=== The Navigation Tree Various Elements of EM.Terrano]]a Propagation Scene ===
== Building A typical propagation scene in EM.Terrano consists of several elements. At a Propagation Scene ==minimum, you need a transmitter (Tx) 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. In EM.Terrano, a transmitter represents a point source, while a receiver represents a point observable. Both a transmitter and a receiver are associated with point objects, which are one of the many types of geometric objects you can draw in the project workspace. Your scene might involve more than one transmitter and possibly a large grid of receivers.
=== The Various Elements A more complicated propagation scene usually contains several buildings, walls, or other kinds of scatterers and wave obstructing objects. You model all of these elements by drawing geometric objects in the project workspace or by importing external CAD models. EM.Terrano does not organize the geometric objects of your project workspace by their material composition. Rather, it groups the geometric objects into blocks based on a Propagation Scene ===common type of interaction with incident rays. EM.Terrano offer the following types of object blocks:
A typical propagation scene in {| class="wikitable"|-! scope="col"| Icon! scope="col"| Block/Group Type ! scope="col"| Ray Interaction Type! scope="col"| Object Types Allowed! scope="col"| Notes|-| style="width:30px;" | [[File:impenet_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Terrano consists Cube's Materials, Sources, Devices & Other Physical Object Types#Impenetrable Surface | Impenetrable Surface]]| style="width:200px;" | Ray reflection, ray diffraction| style="width:250px;" | All solid & surface geometric objects, no curve objects| style="width:300px;" | Basic building group for outdoor scenes|-| style="width:30px;" | [[File:penet_surf_group_icon.png]]| style="width:150px;" | [[Glossary of several elementsEM. At a minimumCube's Materials, you need a transmitter (Tx) at some location Sources, Devices & Other Physical Object Types#Penetrable Surface | Penetrable Surface]]| style="width:200px;" | Ray reflection, ray diffraction, ray transmission in free space| style="width:250px;" | All solid & surface geometric objects, no curve objects| style="width:300px;" | Behaves similar to launch rays into the scene impenetrable surface and a receiver (Rx) at another location uses thin wall approximation for generating transmitted rays, used to receive model hollow buildings with ray penetration, entry and collect 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]]| style="width:200px;" | Ray reflection, ray diffraction| style="width:250px;" | All surface geometric objects, no solid or curve objects | style="width:300px;" | Behaves exactly like impenetrable surface but can change the incoming rayselevation of all the buildings and transmitters and receivers located above it|-| style="width:30px;" | [[File:penet_vol_group_icon. A transmitter 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 a receiver together make the simplest propagation sceneray attenuation inside homogeneous material media| style="width:250px;" | All solid geometric objects, representing no surface or curve objects| style="width:300px;" | Used to model wave propagation inside a free-space linevolumetric 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 ofEM.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;" | Only point objects| style="width:300px;" | Required for the definition of transmitters and receivers|-sight (LOS) channel| style="width:30px;" | [[File:scatterer_group_icon. A transmitter is one png]]| style="width:150px;" | [[Glossary of EM.TerranoCube's several source typesMaterials, while 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 receiver is one radar simulation |-| style="width:30px;" | [[File:Virt_group_icon.png]]| style="width:150px;" | [[Glossary of EM.TerranoCube's several observable Materials, Sources, Devices & Other Physical Object Types#Virtual_Object_Group | Virtual Object]]| style="width:200px;" | No ray interaction| style="width:250px;" | All types. A simpler source type is a Hertzian dipole of objects| style="width:300px;" | Used for representing an almost omninon-directional radiator. A simpler observable is a field sensor that is used to compute the electric and magnetic fields on a specified plane.physical items |}
An outdoor propagation scene may involve several buildings modeled by impenetrable surfaces and an underlying flat ground or irregular terrain surface. An indoor propagation scene may involve several walls modeled by thin penetrable surfaces, a ceiling and a floor arranged according Click on each type to a certain building layout. You can also build mixed scenes involving both impenetrable and penetrable blocks. Your sources and observables can be placed anywhere learn more about it 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 [[Glossary of EM.TerranoCube's Navigation Tree as follows:Materials, Sources, Devices & Other Physical Object Types]].
* '''[[Block_Types#Impenetrable_Surfaces_for_Outdoor_Scenes|Impenetrable Surfaces]]''': feature reflection surfaces, penetrable surfaces, terrain surfaces and diffraction penetrable volumes represent all the objects that obstruct the propagation of impinging electromagnetic waves (rays. Rays hit ) in the facets of this type of blocks and bounce back, but they do not penetrate the objectfree space. It What differentiates them is assumed that the interior types of such blocks or buildings are highly absorptive.* '''[[Block_Types#Penetrable_Surfaces_for_Indoor_Scenes|Penetrable Surfaces]]''': feature reflection, transmission and diffraction of impinging rays. These blocks represent thin surfaces physical phenomena that are used to model their interaction with the exterior and interior walls impinging rays. EM.Terrano discretizes geometric objects into a number of buildingsflat facets. Rays reflect off the surface The field intensity, phase and power of penetrable surfaces and diffract off their edges. They also penetrate the thin surface reflected and continue their path in the free space transmitted rays depend on the other side material properties of the wallobstructing facet.* '''[[Block_Types#Terrain_Surfaces_vs._Global_Ground|Terrain Surfaces]]''': feature reflection and optional diffraction The specular surface of impinging raysa facet can be modeled locally as a simple homogeneous dielectric half-space or as a multilayer medium. These blocks are used to provide one or more impenetrableIn that respect, ground surfaces for all the propagation scene. Rays simply bounce off terrain obstructing objects. * '''[[Block_Types#Penetrable_Volumes|Penetrable Volumes]]''': feature reflection, transmission and diffraction of impinging rays. These blocks are used to model propagation inside general material media or special environments such as fogbuildings, rain and vegetationwalls, terrain, etc.* '''[[#Defining_Base_Point_Sets|Base Points]]'''behave in a similar way: are used to locate a single transmitter or receiver or arrays of transmitters or receivers in the scene.
[[Image:MORE.png|40px]] Click here to learn * They terminate an impinging ray and replace it with one or more about '''[[Block Types]]'''new rays.* They represent a specular interface between two media of different material compositions for calculating the reflection, transmission or diffraction coefficients.
In EMAn outdoor propagation scene typically involves several buildings modeled by impenetrable surfaces.TerranoRays hit the facets of impenetrable buildings and bounce back, but they do not penetrate the various scene elements like object. It is assumed that the interior of such buildingsare highly dissipative due to wave absorption or diffusion. An indoor propagation scene typically involves several walls, terrain objects a ceiling and base points a floor arranged according to a certain building layout. Penetrable surfaces are grouped together based on used to model the exterior and interior walls of buildings. Rays reflect off these surfaces and diffract off their typeedges. All They also penetrate the objects listed under a particular group in the navigation tree share the same color, texture thin surface and material properties. Once a new block group has been created continue their path in the navigation tree, it becomes free space on the "Active" group other side of the project workspace, which is always displayed in bold letterswall. You can start drawing new objects under Terrain surfaces with irregular shapes or possibly random rough surfaces are used as an alternative to the active nodeflat global ground. Any block group You can be made active by right-clicking on its name in the navigation tree also build mixed scenes involving both impenetrable and selecting penetrable blocks or irregular terrain. In the '''Activate''' item context of a propagation scene, penetrable volumes are often used to model block of rain, fog or vegetation. Base location sets are used to geometrically represent point transmitters and point receivers in the contextual menuproject workspace.
It Sometimes it is recommended that you first create block groups, and then helpful to draw new graphical objects under as visual clues in the active block project workspace. These non-physical objects must belong to a virtual object group. However, if you start a new Virtual objects are not discretized by EM.Terrano project from scratch's mesh generator, and start drawing a new object without having previously defined any block groups, a new default impenetrable surface group is created and added to they are not passed onto the navigation tree to hold your new CAD object. You can always change the properties input data files of a block group later by accessing its property dialog from the contextual menu. You can also delete a block group with its objects at any timeSBR simulation engine.
<table><tr><td> [[Image:PROP15PROP MAN2.png|thumb|400pxleft|720px|An urban propagation scene generated by EM.Terrano's Domain Settings "Random City" and "Basic Link" wizards. It consists of 25 cubic brick buildings, one transmitter and a large two-dimensional array of receivers. ]]</td></tr></table> === Organizing the Propagation Scene by Block Groups === In EM.Terrano, all the geometric objects associated with the various scene elements like buildings, terrain surfaces and 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.  <table><tr><td> [[Image:PROP MAN1.png|thumb|left|480px|EM.Terrano's navigation tree.]]</td></tr></table> It is recommended that you first create block groups, and then draw new objects under the active block group. 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 dialogfrom the contextual menu.You can also delete a block group with all of its objects at any time. {{Note|You can only import external CAD models (STEP, IGES, STL, DEM, etc.) only to the CubeCAD module. You can then transfer the imported objects from CubeCAD to EM.Terrano.}} === Moving Objects Among Different Block Groups === You can move any geometric object or a selection of objects from one block group to another. You can also transfer objects among [[EM.Cube]]'s different modules. For example, you often need to move imported CAD models of terrain or buildings from CubeCAD to EM.Terrano. To transfer objects, first select them in the project workspace or select their names in the navigation tree. Then right-click on them and select <b>Move To → Module Name → Object Group</b> from the contextual menu. For example, if you want to move a selected object to a block group called "Terrain_1" in EM.Terrano, then you have to select the menu item '''Move To → EM.Terrano → Terrain_1''' as shown in the figure below. Note that you can transfer several objects altogether using the keyboards's {{key|Ctrl}} or {{key|Shift}} keys to make multiple selections.  <table><tr><td> [[Image:PROP4PROP MAN3.png|thumb|400pxleft|720px|Moving the terrain model of Mount Whitney originally imported from an external digital elevation map (DEM) file to EM.Terrano.]]</td></tr><tr><td>[[Image:PROP MAN4.png|thumb|left|720px|The imported terrain model of Mount Whitney shown in EM.Terrano's Global Ground Settings project workspace under a terrain group called "Terrain_1".]]</td></tr></table> === Adjustment of Block Elevation on Underlying Terrain Surfaces === 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 dialogof a block group and check the box labeled '''Adjust Block to Terrain Elevation'''. All the objects belonging to that 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 have to make sure that the resolution of your terrain, its variation scale and building dimensions are all comparable. Otherwise, on a rapidly varying high-resolution terrain, you will have buildings whose bottoms touch the terrain only at a few points and parts of them hang in the air.}} <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> <table><tr><td> [[Image:PROP MAN6.png|thumb|left|360px|A set of buildings on an undulating terrain without elevation adjustment.]]</td><td>[[Image:PROP MAN7.png|thumb|left|360px|The set of buildings on the undulating terrain after elevation adjustment.]]</td></tr></table> == EM.Terrano's Ray Domain & Global Environment ==
=== Why Do You Need a Finite Computational Domain? ===
* Open the Ray Domain Settings Dialog by clicking the '''Domain''' [[File:image025.jpg]] button of the '''Simulate Toolbar''', or by selecting '''Menu > Simulate > Computational Domain > Settings...''', or by right-clicking on the '''Ray Domain''' item of the navigation tree and selecting '''Domain Settings...''' from the contextual menu, or simply using the keyboard shortcut {{key|Ctrl+A}}.
* 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. Change these values as you like.
* You can also change the color of the domain box using the {{key|Color}} button.
* After changing the settings, use the {{key|Apply}} button to make the changes effective while the dialog is still open.
Â
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[[Image:PROP15.png|thumb|left|480px|EM.Terrano's domain settings dialog.]]
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=== Understanding the Global Ground ===
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 = 0 extending downward. 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.
Alternatively, you can use EM.Terrano's '''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.
{{Note|To model a free-space propagation scene, you have to disable EM.Terrano's default global ground.}}
=== Buildings, Terrain & Obstructing Blocks ===<table><tr><td> [[Image:Global environ.png|thumb|left|720px|EM.Terrano's Global Environment Settings dialog.]]</td></tr></table>
Impenetrable, penetrable and terrain surfaces and penetrable volumes represent buildings, blocks or objects that 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. The field intensity, phase and power of the reflected and transmitted rays depend on the material properties 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:== Defining Point Transmitters & Point Receivers for Your Propagation Scene ==
* They terminate an impinging ray and replace it with one or more new rays.* They represent a specular interface between two media === The Nature of different material compositions for calculating the reflection, transmission and possibly diffraction coefficients.Transmitters & Receivers ===
[[In EM.Terrano]] has generalized , transmitters and receivers are indeed point radiators used for transmitting and receiving signals at different locations of the concept propagation scene. From a geometric point of '''Block''' as any object that obstructs view, both transmitters and affects radio wave propagationreceivers are represented by point objects or point arrays. The following table summarized These are grouped as base locations in the "Physical Structure" section of the navigation tree. As radiators, transmitters and receivers are defined by a radiator type with a certain far-field radiation pattern. Consistent with [[Block Types|block typesEM.Cube]]: 's other computational modules, transmitters are categorizes as an excitation source, while receivers are categorized as a project observable. In other words, a transmitter is used to generate electromagnetic waves that propagate in the physical scene. A receiver, on the other hand, is used to compute the received fields and received signal power or signal-to-noise ratio (SNR). For this reason, transmitters are defined and listed under the "Sources" sections of the navigation tree, while receivers are defined and listed under the "Observables" section.
{| class="wikitable"|-! scope="col"| Block Type! scope="col"|Physical Effects! scope="col"|Legitimate Object Types|-| Impenetrable Surface| Reflection, Diffraction| All solid & surface CAD objects|-| Penetrable Volume| Reflection, Diffraction, Material Medium Transmission| All solid CAD objects|-| Penetrable Surface| Reflection, Diffraction, Thin-Wall Transmission| All solid & surface CAD objects|-| Terrain Surface| Reflection| Specially created tessellated objects only |}EM.Terrano provides three radiator types for point transmitter sets:
[[Image:MORE.png|40px]] Click here to learn more about '''[[Block Types]]'''.#Half-wave dipole oriented along one of the three principal axes#Two collocated, orthogonally polarized, isotropic radiators #User defined (arbitrary) antenna with imported far-field radiation pattern
[[ImageEM.Terrano also provides three radiator types for point receiver sets:prop_manual-12_tn.png|thumb|500px|An imported external terrain model.]]
=== Moving Objects among Block Groups ===#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
You can move one or more selected objects at a time among different block groups. The objects can be selected either in the project workspace, or their names can be selected from the navigation tree. Right click on the highlighted selection default transmitter and select '''Move To > Propagation >''' from the contextual menu. This opens up another subreceiver radiator types are both vertical (Z-menu with a list of all the available block groups already defined in your EMdirected) half-wave dipoles.Terrano project. Select the desired block node, and all the selected objects will move to that block group. In the case of a multiple selection from the navigation tree using the keyboard's {{key|Shift}} key or {{key|Ctrl}} key, make sure that you continue to hold the keyboard's {{key|Shift}} key or {{key|Ctrl}} key down while selecting the destination block group's name from the contextual menu.
In There are three different ways to define a similar way, you can move one transmitter set or more objects from an EM.Terrano block group to one of [[EM.Cube]]'s other modules. In this case, the sub-[[menus]] of the '''Move To >''' item of the contextual menu will indicate all the [[EM.Cube]] modules that have valid groups for transfer of the selected objects. You can also move one or more objects from [[EM.Cube]]'s other modules to a block group in EM.Terrano. receiver set:
{{Note|Except for external terrain models, you can import other external *By defining point objects (STEPor point arrays under physical base location sets in the navigation tree and then associating them with a transmitter or receiver set*Using Python commands emag_tx, IGESemag_rx, STLemag_tx_array, etc.) only to '''[[CubeCAD]]'''. You need to move emag_rx_array, emag_tx_line and emag_rx_line*Using the imported objects form [[CubeCAD]] to EM.Terrano as described above.}}"Basic Link" wizard
=== Defining Base a Point Sets Transmitter Set in the Formal Way ===
[[File:PROP1.png|thumb|300px|[[Propagation Module]]'s Base Set dialog]]EM.Terrano uses '''Point''' objects to position transmitters and receiver Transmitters act as sources in the a propagation scene. Points are regular CAD objects that can be moved around (translated) in the project workspace. The A transmitter is a point objects that are used to represent radiator with a fully polarimetric radiation pattern defined over the transmitters and receivers are grouped together and organized as '''Base Sets''' entire 3D space in the "Physical Structure" section of the navigation treestandard spherical coordinate system. When EM.Terrano gives you move three options for the point objects or change their coordinates, all of their radiator associated transmitters or receivers immediately follow them to the new location. For example, you can define with a grid of receivers using a base set that is made up of a uniformly spaced array of points and spread them in your scene. 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 we discuss placement of transmitters or receivers on an irregular terrain and adjustment of their elevation. point transmitter:
To create a new base set, follow these steps;* Half-wave dipole* Orthogonally polarized isotropic radiators* User defined antenna pattern
* RightBy default, EM.Terrano assumes that your transmitter is a vertically polarized (Z-click on the '''Base Sets''' item of navigation tree and select '''Insert Base Set.directed) resonant half-wave dipole antenna.This antenna has an almost omni-directional radiation pattern in all azimuth directions.''' A dialog for setting up It also has radiation nulls along the Base Set properties opens up.* Enter a name for axis of the base set and dipole. You can change the default blue color if you wish. It is useful to differentiate direction of the base sets associated with transmitters dipole and receivers by their color.* Click orient it along the {key|O}} button to close X or Y axes using the Base Set Dialogprovided 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.
Once a base set node has been added to You can override the navigation tree, it becomes the active node for drawing new objectsdefault radiator option and select any other kind of antenna with a more complicated radiation pattern. Under base setsFor this purpose, you have to import a radiation pattern data file to EM.Terrano. You can only draw point objectsmodel any radiating structure using [[EM. All Cube]]'s other object creation tools are disabledcomputational modules, [[EM. A point is initially drawn on the XY planeTempo]], [[EM. Make sure to change the Z-coordinate of your pointPicasso]], otherwise, your radiator will fall on the global ground at z = 0[[EM. You can also create arrays of base points under the same base setLibera]] or [[EM. This is particularly useful Illumina]], and generate a 3D radiation pattern data file for setting up receiver grids to compute coverage mapsit. Simply select The far-field radiation patter data are stored in a point object specially formatted file with a "'''.RAD'''" file extension. This file contains columns of spherical φ and click θ angles as well as the real and imaginary parts of the complex-valued far-zone electric field components '''Array ToolE<sub>θ</sub>''' of and '''Tools ToolbarE<sub>φ</sub>''' or use the keyboard shortcut . The "theta;A- and "phi;. Enter values for -components of the X, Y or Z spacing as well as far-zone electric field determine the number polarization 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)transmitting radiator.
== Defining Sources & Observables {{Note|By default, EM.Terrano assumes a vertical half-wave dipole radiator for Your Scene ==your point transmitter set.}}
Like every other electromagnetic solver, EM.Terrano's SBR ray tracer requires A transmitter set always needs to be associated with an excitation source and existing base location set with one or more observables for generation of simulation datapoint objects in the project workspace. EM.Terrano offers several types of sources and observables Therefore, you cannot define a transmitter for your scene before drawing a SBR simulation. You can mix and match different source types and observable types depending on the requirements of your modeling problempoint object under a base location set. The available source types are:
* [[#Defining Transmitter Sets Image:Info_icon.png| Transmitter40px]]* Click here to learn how to define a '''[[Asymptotic_Field_Solver Glossary_of_EM.Cube%27s_Materials,_Sources,_Devices_%26_Other_Physical_Object_Types#Point_Transmitter_Set | Hertzian DipolePoint Transmitter Set]]'''.
The available observables types are <table><tr><td> [[Image:Terrano L1 Fig11.png|thumb|left|480px|The point transmitter set definition dialog.]] </td></tr></table>
* 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. [[#Defining Receiver Sets | ReceiverEM.Cube]]* Field Sensor* Far Field Radiation Pattern* Huygens Surface's ".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.
[[Image:MORE.png{{Note|40px]] Click here In order to learn more about defining field sensor observables for modify any of the transmitter set'''[[Data_Visualization_and_Processing#Visualizing_3D_Nears parameters, first you need to select the "User Defined Antenna" option, even if you want to keep the vertical half-Field_Maps | Visualizing 3D Near-Field Maps]]'''wave dipole as your radiator.}}
<table><tr><td> [[ImageFile:MORENewTxProp.png|40px]] Click here to learn more about computing radiation patterns using '''[[Data_Visualization_and_Processing#Far-Field_Observables thumb| Far-Field Observablesleft|720px|The property dialog of a point transmitter set.]]'''.</td></tr></table>
[[Image:MOREYour transmitter in EM.png|40px]] Click here to learn Teranno is indeed more about sophisticated than a simple radiator. It consists of a basic "Transmitter Chain" that contains a voltage source with a series source resistance, and connected via a segment of transmission line to a transmit antenna, which is used to launch the broadcast signal into the free space. The transmitter'''[[Hybrid_Modeling_using_Multiple_Simulation_Engines#Generating_Huygens_Surface_Data s property dialog allows you to define the basic transmitter chain. Click the {{key| Generating Huygens Surface Data]]'''Transmitter Chain}} button of the Transmitter Set dialog to open the transmitter chain dialog. As shown in the figure below, you can specify the characteristics of the baseband/IF amplifier, mixer and 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. Note that the transmit antenna characteristics are automatically filled using the contents of the imported radiation pattern data file. The transmitter Chain dialog also calculates and reports the "Total Transmitter Chain Gain" based on your input. When you close this dialog and return to the Transmitter Set dialog, you will see the calculated value of the Effective Isotropic Radiated Power (EIRP) of your transmitter in dBm.
=== Using {{Note| If you do not modify the default parameters of the transmitter chain, a 50-Ω 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 as a Field Solver ==='s point transmitter chain dialog.]] </td></tr></table>
The simplest SBR simulation can be performed using === Defining a short dipole source with a specified field sensor plane. As an asymptotic EM solver, EM.Terrano then computes the electric and magnetic fields radiated by your dipole source Point Receiver Set in the presence of your multipath propagation environment. EM.Terrano's short dipole source and field sensor observable are very similar to those of [[EM.Cube]]'s other computational modules. You can also compute the far field radiation patterns of a dipole in the presence of surrounding scatterers or compute the Huygens surface data for use in [[EM.Cube]]'s other modules.Formal Way ===
[[Image:MOREReceivers act as observables in a propagation scene.png|40px]] Click here The objective of a SBR simulation is to learn more about using 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 as an '''[[Asymptotic Field Solver]]'''.gives you three options for the radiator associated with a point receiver set:
=== Defining Transmitter Sets ===* Half-wave dipole* Polarization matched isotropic radiator* User defined antenna pattern
A transmitter By default, EM.Terrano assumes that your receiver is a point radiator with a fully defined polarimetric radiation pattern over the entire 3D space in the spherical coordinate systemvertically polarized (Z-directed) resonant half-wave dipole antenna. You can model a radiating structure change the direction of the dipole and orient it along the X or Y axes using [[EMthe provided drop-down list.Cube]]'s FDTD, Planar, MoM3D or PO modules and generate An isotropic radiator has a 3D perfect omni-directional radiation pattern data file for it. These data are stored in a specially formatted file with a "'''all azimuth and elevation directions.RADAn isotropic radiator doesn'''" file extension. It contains columns of spherical φ and θ angles as well as t exist physically in the real and imaginary parts of world, but it can be used simply as a point in space to compute 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.
To You may also define a complicated radiation pattern for your receiver set. In that case, you need to import a radiation pattern data file to EM.Terrano similar to the case of a transmitter source in set. Â {{Note|By default, EM.Terranoassumes a vertical half-wave dipole radiator for your point receiver set.}}Â Similar to transmitter sets, first you need to have at least define a receiver set by associating it with an existing base location set with one '''Base Point''' or more point objects in your the project workspace. In All the "Custom Pattern [[Parameters]]", click receivers belonging to the '''Import Pattern''' button to same receiver set have the path for the radiation data file. This opens up the standard [[Windows]] Open dialog, with the default file same radiator type or extension set to ".RAD". Browse your folders to find the right data file. A radiation pattern file typical propagation scene contains one or few transmitters but usually contains the value a large number of "Total Radiated Power" in its file headerreceivers. This is used by default for power calculations in the SBR simulation. HoweverTo generate a wireless coverage map, you can check the box labeled "'''Custom Power'''" and enter a value for the transmitter power in Wattsneed to define an array of points as your base location set. Â [[EMImage:Info_icon.Cubepng|40px]] can also rotate the imported radiation pattern arbitrarily. In this case, you need Click here to learn how to specify the define a '''Rotation[[Glossary_of_EM.Cube%27s_Simulation_Observables_%26_Graph_Types#Point_Receiver_Set | Point Receiver Set]]''' angles in degrees about the X-, Y- and Z-axes. Note that these rotations are performed sequentially and in order: first a rotation about the X-axis, then a rotation about the Y-axis, and finally a rotation about the Z-axis.
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<td> [[FileImage:PROP20(1)Terrano L1 Fig12.png|thumb|400pxleft|EM.Terrano's Transmitter dialog with a user defined pattern selected.]] </td><td> [[File:PROP20A.png480px|thumb|600px|EM.Terrano's Transmitter Chain The point receiver set definition dialog.]] </td>
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=== Defining Receiver 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:PROP21(1)NewRxProp.png|thumb|400pxleft|EM.Terrano's preliminary Receiver 720px|The property dialog.]] 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 point receiver. 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 a SBR simulation. You define the receivers of your scene by associating them with 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. ]]</td></tr></table>
To define a new In the Receiver Setdialog, go to the Observables section of the Navigation Tree, right click on the there is a drop-down list labeled '''ReceiversSelected Element''' item and select '''Insert Receiver...''' A dialog opens up that , which contains a default name for the new Receiver Set as well as a dropdown list of all the individual receivers belonging to the receiver set. At the end of an SBR simulation, the button labeled '''Select Radiator Set'''{{key|Show Ray Data}} becomes enabled. In Clicking this list button opens the Ray Data dialog, where you will can see a list of all the available base sets that you have already define in received rays at the project workspace. Select selected receiver and designate the desired base set as their computed characteristics. Â If you choose the "user defined antenna" option for your receiver set. Note , it indeed consists of a basic "Receiver Chain" that if the base set contains more than one point, all a receive antenna connected via a segment of them are designated as receivers. After defining transmission line to the low-noise amplifier (LNA) that is terminated in a matched load. The receiver set, 's property dialog allows you to define the points change their color basic receiver chain. Click the {{key|Receiver Chain}} button of the Receiver Set dialog to open the receiver color, which is yellow by defaultchain dialog. The first element As shown in the figure below, you can specify the characteristics of the set is represented by a larger ball LNA such as its gain and noise figure in dB as well as the characteristics of the same color indicating transmission line segment that it is connects the selected receiver in antenna to the sceneLNA. Note that the receiving antenna characteristics are automatically filled from using contents of the radiation file. You have to enter values for antenna's '''Brightness Temperature''' as well as the temperature of the transmission line and the receiver's ambient temperature. The effective '''Receiver Set Dialog Bandwidth''' is also used assumed to access individual receivers of the set be 100MHz, which you can change for data visualization at the end purpose of a simulationnoise 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 button labeled "Show Ray Data" becomes enabled. Clicking this button opens receiver power and signal-noise ratio (SNR) of the Ray Data Dialogselected receiver are calculated and they are reported in the receiver set dialog in dBm and dB, where you respectively. You can see a list examine the properties of all the received rays at individual receivers and all the selected individual rays received by each receiver and their computed characteristicsin your receiver set using the "Selected Element" drop-down list.
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<td> [[File:PROP22NewRxChain.png|thumb|400pxleft|EM.Terrano's Receiver dialog with an isotropic radiator selected.]] </td><td> [[File:PROP22A.png|thumb|600px720px|EM.Terrano's Receiver Chain point receiver chain dialog.]] </td>
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=== Adjustment of Tx/Rx Elevation above a Terrain Surface Modulation Waveform and Detection ===
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 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 the specified height. EM.Terrano gives allows you the option to adjust the transmitter and receiver sets to the terrain elevation. This is done define a digital modulation scheme for individual transmitter sets and individual receiver setsyour communication link. At the top of the Transmitter Dialog there is a check box labeled "'''Adjust Tx Sets There are currently 17 waveforms 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 choose from 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. property dialog:
To better understand why there are two separate sets *OOK*M-ary ASK*Coherent BFSK*Coherent QFSK*Coherent M-ary FSK*Non-Coherent BFSK*Non-Coherent QFSK*Non-Coherent M-ary FSK*BPSK*QPSK*Offset QPSK*M-ary PSK*DBPSK*pi/4 Gray-Coded DQPSK*M-ary QAM*MSK*GMSK (BT = 0.3) In the above list, you need to specify the '''No. Levels (M)''' 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 points 100MHz. Once 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 (BER) is calculated. The Shannon â Hartley Equation estimates the channel capacity: <math> C = B \log_2 \left( 1 + \frac{S}{N} \right) </math> where B in the scenebandwidth in Hz, note that a point array and C is the channel capacity (CAD objectmaximum data rate) expressed in bits/s. The spectral efficiency of the channel is used defined as <math> \eta = \log_2 \left( 1 + \frac{S}{N} \right) </math> The quantity E<sub>b</sub>/N<sub>0</sub> is the ratio of energy per bit to create noise power spectral density. It is a uniformly spaced base setmeasure of SNR per bit and is calculated from the following equation: <math> \frac{E_b}{N_0} = \frac{ 2^\eta - 1}{\eta} </math> where η is the spectral efficiency.  The array object always preserves its grid topology as you move it around relationship between the scenebit error rate and E<sub>b</sub>/N<sub>0</sub> depends on the modulation scheme and detection type (coherent vs. Howevernon-coherent). For example, for coherent QPSK modulation, one can write: <math> P_b = 0.5 \; \text{erfc} \left( \sqrt{ \frac{E_b}{N_0} } \right) </math> where P<sub>b</sub> is the transmitters or receivers associated with this point array object are elevated above bit error rate and erfc(x) is the irregular terrain complementary error function: <math> \text{erfc}(x) = 1-\text{erf}(x) = \frac{2}{\sqrt{\pi}} \int_{x}^{\infty} e^{-t^2} dt </math> The '''Minimum Required SNR''' parameter is used to determine link connectivity between each transmitter and no longer follow a strictly uniform gridreceiver pair. If you move check the base box labeled '''Generate Connectivity Map''' in the receiver set from its original position property dialog, a binary map of the propagation scene is generated by EM.Terrano, in which one color represents a closed link and another represent no connection depending on the selected color map type of the graph. EM.Terrano also calculates the '''Max Permissible BER''' corresponding to the specified minimum required SNR and displays it in the receiver set property dialog. === A Note on EM.Terrano's Native Dipole Radiators === When you define a new locationtransmitter set or a new receiver set, EM.Terrano assigns a vertically polarized half-wave dipole radiator to the base points' topology will stay intactset 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, while the associated transmitters or receivers will far-zone electric field of a vertically-polarized dipole antenna can be redistributed above expressed as:  <math> E_\theta(\theta,\phi) \approx j\eta_0 I_0 \frac{e^{-jk_0 r}}{2\pi r} \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] </math> <math> E_\phi(\theta,\phi) \approx 0 </math> where k<sub>0</sub> = 2π/λ<sub>0</sub> is the terrain based 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 their new elevationsthe dipole, and L is the length of the dipole. The directivity of the dipole antenna is given be the expression: <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> with  <math> F_1(x) = \gamma + \text{ln}(x) - C_i(x) </math> <math> F_2(x) = \frac{1}{2} \text{sin}(x) \left[ S_i(2x) - 2S_i(x) \right] </math> <math> F_3(x) = \frac{1}{2} \text{cos}(x) \left[ \gamma + \text{ln}(x/2) + C_i(2x) - 2C_i(x) \right] </math>  where γ = 0.5772 is the Euler-Mascheroni constant, and C<sub>i</sub>(x) and S<sub>i</sub>(x) are the cosine and sine integrals, respectively:  <math> C_i(x) = - \int_{x}^{\infty} \frac{ \text{cos} \tau}{\tau} d\tau </math> <math> S_i(x) = \int_{0}^{x} \frac{ \text{sin} \tau}{\tau} d\tau </math>  In the case of a half-wave dipole, L = λ<sub>0</sub>/2, and D<sub>0</sub> = 1.643. Moreover, the input impedance of the dipole antenna is Z<sub>A</sub> = 73 + j42.5 Ω. These dipole radiators are connected via 50Ω transmission lines to a 50Ω source or load. Therefore, there is always a certain level of impedance mismatch that violates the conjugate match condition for maximum power.
<table>
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<td> [[ImageFile:prop_txrx1_tnDipole radiators.png|thumb|400px720px|Transmitters and receivers adjusted above an uneven terrain surfaceEM.]] </td><td> [[Image:prop_txrx2_tn.png|thumb|400px|The associated base point sets with the adjusted transmitters Terrano's native half-wave dipole transmitter and receivers on the terrainreceiver.]] </td>
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</table>
== Discretizing On the Propagation Scene ==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>θ</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:
=== Why Do You Need to Discretize the Scene? ===* DPL_STD_X.RAD* DPL_STD_Y.RAD* DPL_STD_Z.RAD
EM.Terrano's SBR ray tracer uses a method known as Geometrical Optics (GO) and they are located in conjunction with the Uniform Theory of Diffraction (UTD) to traces the rays from their originating point at the source to the individual receiver locations. Ray may hit obstructing objects folder "\Documents\EMAG\Models" on their way and get reflected, diffracted or transmittedyour computer. EM.Terrano's SBR solver can only handle diffraction off linear edges and reflection from Note that these are full-wave simulation data and transmission through planar material interfacesdo not involve any approximate assumptions. The underlying theory for calculation of reflectionTo use these files as an alternative to the native dipole radiators, transmission and diffraction coefficients indeed assumes material media of infinite extents. When a ray hits a specular point on you need to select the surface of '''User Defined Antenna Pattern''' radio button as the obstructing object, a local planar surface assumption is made at the specular pointradiator type in the transmitter or receiver set property dialog.
[[Image:MORE.png|40px]] Click here to learn more about === A Note on the theory Rotation of '''[[SBR Method]]'''.Antenna Radiation Patterns ===
If your propagation scene contains only cubic buildings on the flat global ground, the assumptions of linear edges EM.Terrano's Transmitter Set dialog and planar facets hold well although they violate the infinite extents assumptionReceiver Set dialog both allow you to rotate an imported radiation pattern. In many practical scenariosthat case, however, your buildings may have curved surface or the terrain may be irregular. EM.Terrano allows you need to draw any type of surface or solid CAD objects under impenetrable specify the '''Rotation''' angles in degrees about the X-, Y- and penetrable surface groups or penetrable volumesZ-axes. Some of It is important to note that these objects contain curved surfaces or curved boundaries rotations are performed sequentially and edges such as cylindersin the following order: first a rotation about the X-axis, conesthen a rotation about the Y-axis, etcand finally a rotation about the Z-axis. In order to address all such cases in the most general contextaddition, EM.Terrano always uses a triangular surface mesh of all the objects in your propagation scene. Even rectangular facets of cubic buildings rotations are meshed using triangular cellsperformed with respect to the "rotated" local coordinate systems (LCS). This In other words, the first rotation with respect to the local X-axis transforms the XYZ LCS to a new primed X<sup>′</sup>Y<sup>′</sup>Z<sup>′</sup> LCS. The second rotation is done performed with respect to be able the new Y<sup>′</sup>-axis and transforms the X<sup>′</sup>Y<sup>′</sup>Z<sup>′</sup> LCS to properly discretize composite buildings made of conjoined cubic objectsa new double-primed X<sup>′′</sup>Y<sup>′′</sup>Z<sup>′′</sup> LCS. The third rotation is finally performed with respect to the new Z<sup>′′</sup>-axis. The figures below shows single and double rotations.
Unlike <table><tr><td> [[EMFile:PROP22B.png|thumb|300px|The local coordinate system of a linear dipole antenna.Cube]]'s other computational modules, </td><td> [[File:PROP22C.png|thumb|600px|Rotating the density or resolution of EMdipole antenna by +90° about the local Y-axis.Terrano's surface mesh does not depend on ]] </td></tr></table><table><tr><td> [[File:PROP22D.png|thumb|720px|Rotating the operating frequency dipole antenna by +90° about the local X-axis and is not expressed in terms of then by -45° by the wavelengthlocal Y-axis. Its sole purpose ]] </td></tr></table> === Adjustment of Tx/Rx Elevation above a Terrain Surface === 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 discretize curved zero everywhere. In many propagation modeling problems, your transmitters and receivers may be located above an irregular scatterers into flat facets and linear edgesterrain with varying elevation across the scene. ThereforeIn that case, geometrical fidelity 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 only criterion sum of the terrain elevation at the base point and the specified height. EM.Terrano 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 quality top of an SBR meshthe Transmitter Dialog there is a check box labeled "'''Adjust Tx Sets to Terrain Elevation'''". It Similarly, at the top of the Receiver Dialog there is important a check box labeled "'''Adjust Rx Sets to note that discretizing smooth objects using Terrain Elevation'''". These boxes are unchecked by default. As a triangular surface mesh typically creates 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 large number of small edges among transmitter set or a receiver set above an irregular terrain, the facets that transmitters or receivers are simply mesh artifacts and should not be considered elevated from the location of their associated base points by the amount of terrain elevation as diffracting edgescan be seen in the figure below. For example, each rectangular face  To better understand why there are two separate sets of points in the scene, note that a cubic building point array (CAD object) is subdivided into four triangles along the two diagonalsused to create a uniformly spaced base set. The four internal edges lying inside array object always preserves its grid topology as you move it around the face scene. However, the transmitters or receivers associated with this point array object are obviously not diffracting edgeselevated above the irregular terrain and no longer follow a strictly uniform grid. A lot of subtleties like these must be taken into account by If you move the SBR solver base set from its original position to run accurate and computationally efficient simulationsa 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.
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<td> [[Image:PROP20BPROP MAN8.png|thumb|400pxleft|Two building objects, one cubic 640px|A transmitter (red) and the other cylindricala grid of receivers (yellow) adjusted above a plateau terrain surface.]] </td><td> [[Image:PROP20C.png|thumb|400px|The default mesh of underlying base point sets (blue and orange dots) associated with the two building objectsadjusted transmitters and receivers on the terrain are also visible in the figure.]] </td>
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=== Viewing & Modifying Discretizing the SBR Mesh =Propagation Scene in EM.Terrano ==
=== Why Do You can view and examine the discretized version of your scene objects as they are sent Need to Discretize 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 {{key|Ctrl+M}}. A triangular surface mesh of your physical structure appears in the project workspace. In this case, EM.Terrano 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.Terrano's Normal View, press the {{key|Esc}} key of the keyboard, or click the Mesh button of the Simulate Toolbar once again.Scene? ===
You can adjust EM.Terrano's SBR solver uses a method known as Geometrical Optics (GO) in conjunction with the mesh resolution and increase the geometric fidelity Uniform Theory of discretization by creating more and finer triangular facets. On the other hand, you may want Diffraction (UTD) to reduce trace the mesh complexity and send rays from their originating point at the source to the SBR engine only a few coarse facets to model your buildingsindividual receiver locations. To adjust the mesh resolutionRays may hit obstructing objects on their way and get reflected, open the Mesh Settings Dialog by clicking the '''Mesh Settings''' [[File:mesh_settings.png]] button of the Simulate Toolbar diffracted or select '''Simulate > Discretization >''' '''Mesh Settings.transmitted.EM.Terrano'''s SBR solver can only handle diffraction off linear edges and reflection from and transmission through planar interfaces. This dialog provides a single [[parameters]]: '''Edge Mesh Cell Size'''When an incident ray hits the surface of the obstructing object, which has a default value local planar surface assumption is made at the specular point. The assumptions of 100 project units. If you are already linear edges and planar facets obviously work in the Mesh View Mode case of a scene with cubic buildings and open the Mesh Settings Dialog, you can see the effect of changing the mesh cell size using the {{key|Apply}} buttona flat global ground.
Some additional mesh [[parameters]] can be accessed by clicking the {{key|Tessellation Options}} button of the dialog. In the Tessellation Options dialogmany practical scenarios, you can change 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 penetrable surface groups or penetrable volumes. EM.Terrano'''Curvature Angle Tolerance''' expressed s mesh generator creates a triangular surface mesh of all the objects in degreesyour propagation scene, which has is called a default value facet mesh. Even the walls of 45°cubic buildings are meshed using triangular cells. This parameter can affect the shape enables EM.Terrano to properly discretize composite buildings made of the mesh especially in the case of solid CAD conjoined cubic objects with curved surfaces. Note that unlike  Unlike [[EM.Cube]]'s other computational modules that express , the default mesh density based 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 solver to run accurate and computationally efficient simulations.  === Generating the Facet Mesh === You 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 use set a smaller mesh cell size 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.
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<td> [[Image:prop_manual-29.png|thumb|350pxleft|EM.Terrano's Mesh Settings dialog.]] </td><td> [[Image:prop_manual-29A.png|thumb|350px480px|EM.Terrano's Tessellation Options mesh settings dialog.]] </td><td> [[Image:PROP20D.png|thumb|400px|The refined mesh of the two building objects with an edge length of 10m and a curvature angle tolerance of 10°.]] </td>
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[[Image:Info_icon.png|30px]] Click here to learn more about '''[[Preparing_Physical_Structures_for_Electromagnetic_Simulation#Working_with_EM.Cube.27s_Mesh_Generators | Working with Mesh Generator]]'''.
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[[Image:Info_icon.png|30px]] Click here to learn more about the properties of '''[[Glossary_of_EM.Cube%27s_Simulation-Related_Operations#Facet_Mesh | EM.Terrano's Facet Mesh Generator]]'''.
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<td> [[Image:PROP15BUrbanCanyon2.png|thumb|550pxleft|640px|The brick facet mesh of the buildings in an the urban propagation scenegenerated by EM.Terrano's Random City wizard with a cell edge length of 100m.]] </td></tr><tr><td> [[Image:PROP15CUrbanCanyon3.png|thumb|550pxleft|640px|The triangular surface facet mesh of the building buildings in the urban propagation scenegenerated by EM.Terrano's Random City wizard with a cell edge length of 10m.]] </td>
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== Running an SBR Simulation Ray Tracing Simulations in EM.Terrano ==Â EM.Terrano provides a number of different simulation or solver types:
=== * 3D Field Solver* SBR Simulation Types ===Channel Analyzer* Log-Haul Channel Analyzer* Communication Link Solver* Radar Link Solver
[[Image:PROP12The first three simulation types are described below.png|thumb|400px|For a description of EM.Terrano's Simulation Run dialogRadar Simulator, follow this link.]]EM.Terrano offers three types of ray tracing simulations:
* === Running a Single-Frequency SBR Analysis* Frequency Sweep* Parametric Sweep===
Its main solver is the '''3D SBR Ray Tracer'''. Once you have set up your propagation scene in EM.Terrano and have defined sources/transmitters and observables/receivers for your scene, you are ready to run a SBR ray tracing simulation. You set the simulation mode in EM.Terrano's simulation run dialog. A single-frequency SBR analysis is a single-run simulation and the simplest type of ray tracing simulation and in EM.Terrano. It involves the following steps:
* Set the unit units of your project scene 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.
* Visualize the coverage map and plot other data.
You can access EM.Terrano's Simulation Run dialog by clicking the '''Run''' [[File:run_icon.png]] button of the '''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 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> [[Image:Terrano L1 Fig16.png|thumb|left|480px|EM.Terrano's simulation run dialog.]] </td></tr></table> <table><tr><td> [[Image:PROP MAN10.png|thumb|left|550px|EM.Terrano's output message window.]] </td></tr></table>
=== Changing the SBR Engine Settings ===
[[Image:PROP13.png|thumb|400px|EM.Terrano's SBR Engine Settings dialog.]]There are a number of SBR simulation settings that can be accessed and changed from the SBR Ray Tracing Engine Settings Dialog. To open this dialog, click the button labeled {{key|Settings}} on the right side of the '''Select EngineSimulation or Solver Type''' dropdown 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 ray tracing process. You can selectively enable or disable '''Reflection/Transmission''', and '''Edge Diffraction''' and '''Terrain Diffraction''' in the "Ray-Block Interactions" section of this dialog. By default, the ray reflection, and transmission and edge diffraction effects are enabled and the terrain diffraction effects are disabled. 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: '''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 5 one project units.
As rays travel in the scene and bounce from surfaces, they lose their power, and their amplitudes gradually diminish<table><tr><td> [[Image:PROP MAN11. From a practical point of view, only rays that have power levels above the receiver sensitivity threshold can be effectively receivedpng|thumb|left|720px|EM. Therefore, all the rays whose power levels fall below a specified power threshold are discarded. The Terrano'''Ray Power Threshold''' is specified in dBm and has a default value of -100dBm. Keep in mind that the value of this threshold directly affects the accuracy of the s SBR simulation results as well as the size of the output data fileengine settings dialog.]] </td></tr></table>
You can also set the '''Angular Resolution''' of the transmitter As rays travel in degreesthe scene and bounce from surfaces, they lose their power, and their amplitudes gradually diminish. By default, every transmitter emanates equi-angular ray tubes at From a resolution practical point of 1 degree. Lower angular resolutions larger than 1° speed up the SBR simulation significantlyview, but they may compromise only rays that have power levels above the accuracyreceiver sensitivity can be effectively received. Higher angular resolutions less than 1° increase the accuracy of the simulating resultsTherefore, but they also increase all the computation timerays whose power levels fall below a specified power threshold are discarded. The SBR Engine Settings dialog also shows the required '''Minimum Angular ResolutionRay Power Threshold''' is specified in degrees in dBm and has a greyeddefault value of -out box150dBm. This number is calculated based on Keep in mind that the overall extents value of your computational domain this threshold directly affects the accuracy of the simulation results as well as the SBR mesh resolution. To see this value, you have to generate the SBR mesh first. Keeping the angular resolution size 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 simulationoutput data file.
=== Running an You can also set the '''Ray Angular Resolution''' of the transmitter rays in degrees. By default, every transmitter emanates equi-angular ray tubes at a resolution of 1 degree. Lower angular resolutions larger than 1° speed up the SBR Frequency Sweep ===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.
[[Image:prop_run10.png|thumb|300px|EM.Terrano's Frequency Settings dialoggives a few more options for the ray tracing solution of your propagation problem.]]By defaultFor instance, it allows you to exclude the direct line-of-sight (LOS) rays from the final solution. There is a check box for this purpose labeled "Exclude direct (LOS) rays from the solution", which is unchecked by default. EM.Terrano performs a single-frequency analysisalso allows you to superpose the received rays incoherently. You set In that case, the operational frequency powers of a SBR simulation individual ray are simply added to compute that total received power. This option in the project's '''Frequency Dialog'''check box labeled "Superpose rays incoherently" is disabled by default, which can be accessed in a number of ways:too.
* By clicking At the '''Frequency''' [[File:freq_icon.png]] button end of a ray tracing simulation, the '''Simulate Toolbar'''electric field of each individual ray is computed and reported.* By selecting '''Simulate > Frequency Settings.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''' from the Menu Bars E-field based on receiver pattern", which is unchecked by default.* Using If this box is checked, the keyboard shortcut {{key|Ctrl+F}}.* By double clicking the frequency section (box) field of each ray is normalized so as to reflect that effect of the receiver antenna'''Status Bar'''s radiation pattern. The received power of each ray is calculated from the following equation:
You <math> P_{ray} = \frac{ | \mathbf{E_{norm}} |^2 }{2\eta_0} \frac{\lambda_0^2}{4\pi} </math> It can also select 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. === Polarimetric Channel Analysis === In a 3D SBR simulation, a transmitter shoots a large number of rays in all directions. The electric fields of these rays are polarimetric and their strength and polarization are determined by the designated radiation pattern of the transmit antenna. The rays travel in the propagation scene and bounce from the ground and buildings or other scatterers or get diffracted at the building edges until they reach the location of the receivers. Each individual ray has its own vectorial electric field and power. The electric fields of the received rays are then superposed coherently and polarimetrically to compute the total field at the receiver locations. The designated radiation pattern of the receivers is then used to compute the total received power by each individual receiver. From 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 ''Frequency Sweep'E<sub>θ</sub>'' option in the 'and ''Simulation Mode'E<sub>φ</sub>'' dropdown list of ' field components associated with each ray at the receiver location to its '''Run DialogE<sub>θ</sub>'''and '''E<sub>φ</sub>''' field components at the transmitter location. Click Each ray has a delay and θ and φ angles of departure at the {{key|Settings}} button on transmitter location and θ and φ angles of departure at the right side receiver location. To perform a polarimatric channel characterization of this dropdown list to your propagation scene, open up the Frequency Settings DialogEM. In this Terrano's Run Simulation dialog you have to set the value of and select '''Start FrequencyChannel Analyzer''', from the drop-down list labeled '''End FrequencySelect Simulation or Solver Type''' . At the end of the 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. === The "Near Real-Time" Polarimatrix Solver === After EM.Terrano's channel analyzer generates a ray database that characterizes your propagation channel polarimetrically for all the combinations of transmitter and receiver locations, a ray tracing solution of the propagation problem can readily be found in almost real time by incorporating the effects of the radiation patterns of transmit and receive antennas. This is done using the ''Number 'Polarimatrix Solver''', which is the third option of Samplesthe drop-down list labeled ''' for you frequency Select Simulation or Solver Type''' in EM.Terrano's Run Simulation dialog. The results of the Polarimatrix and 3D SBR solvers must be identical from a theoretical point of view. However, there might be small discrepancies between the two solutions due to roundoff errors. Using the Polarimatrix solver can lead to a significant reduction of the total simulation time in sweepsimulations that involve a large number of transmitters and receivers. Once you click Certain simulation modes of EM.Terrano are intended for the Polarimatrix solver only as will be described in the next section.  {{keyNote|RunIn order to use the Polarimatrix solver, you must first generate a ray database of your propagation scene using EM.Terrano's Channel Analyzer.}} button,  === EM.Terrano performs 's Simulation Modes === EM.Terrano provides a number of different simulation modes that involve single or multiple simulation runs:  {| class="wikitable"|-! scope="col"| Simulation 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 sweep by assigning each 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 current operational 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 running requires an existing ray database|-| style="width:120px;" | [[#Rotational_Sweep | Rotational Sweep]]| style="width:180px;" | Rotates the SBR 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 engine 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|} Click on each item in the above list to learn more about each simulation mode.  You set the simulation mode in EM.Terrano's simulation run dialog using the drop-down list labeled '''Simulation Mode'''. A single-frequencyanalysis is a single-run simulation. All the other simulation modes in the above list are considered multi-run simulations. In multi-run simulation modes, certain parameters are varied and a collection of simulation data at all frequency samples files are saved into generated. At the end of a sweep simulation, you can plot the output parameter results on 2D graphs or you can animate the 3D simulation data files including "SBR_results.RTOUT"from the navigation tree.
{{Note| EM.Terrano's frequency sweep simulations are very fast because the geometrical optics (ray tracing) part of the simulation is frequency-independent.}}
[[Image:MORE.png|40px]] Click here to learn more about '''[[Parametric_Modeling,_Sweep_%26_Optimization#Running_Parametric_Sweep_Simulations_in_EM.Cube | Running Parametric === Transmitter Sweep Simulations in EM.Cube]]'''.===
== Working When your propagation scene contains two or more transmitters, whether they all belong to the same transmitter set with SBR Simulation Data ==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.
=== {{Note| EM.Terrano's Output Simulation Data ===transmitter sweep works only with the Polarimatrix Solver and requires an existing ray database previously generated using the Channel Analyzer.}}
At the end of an SBR 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. From the ray data, the total electric field at the location of receivers as well as the received power are computed. The 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 temperature, noise figure levels and transmission line losses in the definition of the receiver sets, the noise power level and signal-to-noise ratios (SNR) at each receiver are also calculated. If you define a field sensor, or a far field observable, or a Huygens surface for your project, your output simulation data will include near-field distribution maps, far field radiation patterns or Huygens surface data files, respectively. === Rotational Sweep ===
=== Visualizing Field & Received Power Coverage Maps ===You can rotate the 3D radiation patterns of both 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.
As an asymptotic EM simulator, {{Note| EM.Terrano computes 's rotational sweep works only with the polarimetric electric field at every receiver location including amplitude Polarimatrix Solver and phase of all three X, Y, Z field components as well as requires an existing ray database previously generated using the total field magnitudeChannel Analyzer. In wireless propagation modeling for communication system applications, the received power at the receiver location is more important than the field values. Wireless coverage maps commonly refer to the received power levels at different locations in a given site. 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]].=== Mobile Sweep ===
The received power P<sub>r</sub> In a mobile sweep, each transmitter is paired with a receiver according to their indices in dBm their parent sets. At each simulation run, only one (Tx, Rx) pair is found from 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 following equation:scene must be equal. Otherwise, EM.Terrano will prompt an error message.
<math> P_r [dBm[EM.Cube] = P_t ] 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 [dBm[Glossary_of_EM.Cube%27s_Wizards#Mobile_Path_Wizard | Mobile Path Wizard]] + 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 {{Note| EM.Terrano is fully polarimetric. The transmitting and receiving antenna characteristics are specified through 's mobile sweep works only with the imported radiation pattern files, which are part of the definition of the transmitters Polarimatrix Solver and receivers. In particular, requires an existing ray database previously generated using the polarization mismatch losses are taken into account through the polarimetric SBR ray tracing analysisChannel Analyzer. }}
EM.Terrano's transmitters always require === Investigating Propagation Effects Selectively One at a radiation pattern file unless you use a short dipole source to excite your structure. On the other hand, EM.Terrano's default receivers are assumed to be isotropic radiators. Although isotropic radiators do not exist as actual physical antennas, they make convenient and useful theoretical observables for the purpose of power coverage map calculations. EM.Terrano's isotropic receiving radiators are assumed to be polarization-matched to the incoming rays. As such, they have a unity gain and do not exhibit any polarization mismatch losses. 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 an a SBR simulation, you can visualize the field maps and receiver received power coverage map of your receiver sets. A coverage map shows propagation scene, which appears under the total '''Received Power''' by each of the receivers and is visualized as a color-coded intensity plot. Under each receiver set node item in the navigation tree, a total of seven field maps together with a . The figure below shows the received power coverage map are added. The field maps include amplitude and phase plots for of the three X, Y, Z field components plus random city scene with a total electric field plotvertically polarized half-wave dipole transmitter located 10m above the ground and a large grid of vertically polarized half-wave dipole receivers placed 1. To display a field or coverage map, simply click on its entry in 5m above the navigation treeground. The 3D plot appears in the Main Window overlaid on your propagation scene. A legend box on the right shows the limits of the color scale and units (dB). The 3D coverage maps are displayed map between -23dBm as horizontal confetti above the receivers. You can change the appearance of the receivers maximum and maps from the property dialog of -150dB (the default receiver set. You can further customize sensitivity value) as the settings of the 3D field and coverage plotsminimum.
<table><tr><td> [[Image:MOREUrbanCanyon10.png|40px]] Click here to learn more about '''[[Data_Visualization_and_Processing#Visualizing_3D_Near-Field_Maps thumb| Visualizing 3D Near-Field Mapsleft|640px|The received power coverage map of the random city scene with a dipole transmitter.]]'''.</td></tr></table>
At Sometime it is helpful to change the end scale of a frequency sweep or parametric sweep SBR simulation, as many coverage maps as the number of sweep variable samples are generated and added color map to better understand the navigation tree. In this case dynamic range of the additional seven field maps are saved to avoid a cluttered navigation treecoverage map. You can If you double-click on the legend or right-click on each of the coverage maps corresponding to each of map's name in the variable samples navigation tree and visualize it in select '''Properties''', the project workspacePlot Settings dialog opens up. You can also animate Select the coverage maps on '''User-Defined''' item and set the navigation treelower and upper bounds of color map as you wish.
<table><tr><td> [[Image:MOREUrbanCanyon15.png|40pxthumb|left|480px|The plot settings dialog of the coverage map.]] Click here to learn more about '''</td></tr></table><table><tr><td> [[Data_Visualization_and_Processing#3D_Near_Image:UrbanCanyon16.26_Far_Field_Animation png| Animating 3D Nearthumb|left|640px|The received power coverage map of the random city scene with a user-Field Mapsdefined color map scale between -80dBm and -20dBm.]]'''</td></tr></table>Â 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.
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<td> [[Image:prop_run11_tnUrbanCanyon14.png|thumb|550pxleft|Received power coverage map of an urban 640px|EM.Terrano's simulation run dialog showing the check boxes for controlling various propagation sceneeffects.]] </td><td> [[Image:prop_run12_tn.png|thumb|550px|Total electric field map of an urban propagation scene.]] </td>
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=== Calculating <table><tr><td> [[Image:UrbanCanyon11.png|thumb|left|640px|The received power coverage map of the SNR & Visualizing Connectivity Maps===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, noisefigure and transmission line losses in the definition of the receiver sets, the noise power level and signal-related 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 [parameters]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.
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<td> [[Image:PROP15AAnnArbor Scene1.png|thumb|550pxleft|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 an urban propagation the Ann Arbor scene with minimum SNR level set to 25dB<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>
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=== Visualizing the Rays in the Scene ===
[[Image:PROP12B.png|thumb|420px|EM.Terrano's Ray Data dialog.]]
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 Data''', 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 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.
Â
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[[Image:UrbanCanyon17.png|thumb|left|720px|EM.Terrano's ray data dialog showing a selected ray.]]
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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).
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<td> [[Image:prop_run5_tnUrbanCanyon18.png|thumb|550pxleft|640px|Visualization of received rays at the location of the a selected receiverin 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* Real and imaginary parts of the three E<sub>x</sub>, E<sub>y</sub>, E<sub>z</sub> components* Number of ray hit points * Coordinates 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. <table><tr><td> [[Image:prop_run6_tnprop_run8_tn.png|thumb|550pxleft|Analyzing a selected ray from the ray 720px|A typical SBR output data dialogfile.]] </td>
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=== Plotting Other Simulation Results ===
Besides visualizing the coverage map and received rays "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 the [[EM.Cube|EM.CUBE]]'s [[Propagation Module]], you Data Manager. You can also plot open data manager by clicking the '''Path LossData Manager''' [[File:data_manager_icon.png]] button of all the receivers belonging to a receiver set as well as the '''Power Delay ProfileSimulate Toolbar''' of individual receivers. To plot these data, go the or by selecting '''ObservablesMenu > Simulate > Data Manager''' section of from the Navigation Tree and menu bar or by right click -clicking on the '''ReceiversData Manager''' item. From of the context menu, select navigation tree and selecting '''Plot Path LossOpen Data Manager...''' from the contextual menu or '''Plot Power Delay Profile''', respectively. The path loss data between the active transmitter and all the receivers belonging 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 using 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 chartkeyboard shortcut {{key|Ctrl+D}}.
You can also plot the path loss and power delay profile graphs and many others from [[EM.Cube|EM.CUBE]]'s The available data manager. You can open data manager by clicking files in the '''"2D Data Manager''' [[File:data_manager_icon.png]] button Files" tab of the '''Compute Toolbar''' or by selecting '''Compute [[File:larrow_tn.png]] 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 '''Ctrl+D'''. In the Data manager Dialog, you will see a list of all the data files available for plotting. These Manger include the theta and phi angles of arrival and departure of the selected receiver. You can select any data file by clicking and highlighting its '''ID''' in the table and then clicking the '''Plot''' button.:
* '''Path Loss''': The channel path loss is defined as PL === Output P<sub>r</sub> - EIRP. The path loss data are stored in a file called "SBR_receiver_set_name_PATHLOSS.DAT" as a function of the receiver index. The path loss data make sense only if your receiver set has the default isotropic radiator. * '''Power Delay Profile''': The 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.DAT". You can plot these data from the Data Files ===Manager as a bar chart called the power delay profile. The bars indeed correspond to the difference between the ray power in dBm and the minimum power threshold level in dBm, which makes them a positive quantity. * '''Angles of Arrival''': These are the Theta and Phi angles of the individual rays received by the selected receiver and saved to the files "SBR_receiver_set_name_ThetaARRIVAL.ANG" and "SBR_receiver_set_name_PhiARRIVAL.ANG". You can plot them in the Data Manager in polar stem charts.
At the end When you run a frequency or parametric sweep in [[EM.Terrano]], a tremendous amount of an SBR simulationdata may be generated. [[EM.Terrano]] only stores the '''Received Power''', '''Path Loss''' and '''SNR''' of the results are written into a main output selected receiverin ASCII data file with files called "PREC_i.DAT", "PL_i.DAT" and "SNR_i.DAT", where is the reserved name index of SBR_Resultsthe receiver set in your scene.RTOUTThese quantities are tabulated vs. This file has the following format:sweep variable's samples. You can plot these files in EM.Grid.
NEW LINE[[Image:Info_icon.png|40px]] Click here to learn more about working with data filed and plotting graphs in [[EM.Cube]]'s '''[[Defining_Project_Observables_%26_Visualizing_Output_Data#The_Data_Manager | Data Manager]]'''.
* Receiver Number<table>* Receiver Base X, Y , Z Coordinates<tr>* Receiver Height<td> [[Image:Terrano pathloss.png|thumb|360px|Cartesian graph of path loss.]] </td><td> [[Image:Terrano delay.png|thumb|360px|Bar graph of power delay profile.]] </td></tr><tr><td> [[Image:Terrano ARR phi.png|thumb|360px|Polar stem graph of Phi angle of arrival.]] </td><td> [[Image:Terrano ARR theta.png|thumb|360px|Polar stem graph of Theta angle of arrival.]] </td></tr><tr><td> [[Image:Terrano DEP phi.png|thumb|360px|Polar stem graph of Phi angle of departure.]] </td><td> [[Image:Terrano DEP theta.png|thumb|360px|Polar stem graph of Theta angle of departure.]] </td></tr></table>
NEW LINE:=== Visualizing 3D Radiation Patterns of Transmit and Receive Antennas in the Scene ===
Number When you designate a "User Defined Antenna Pattern" as the radiator type of Raysa 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 actual location of the transmitter or receiver. To do so, you have to define a 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 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 scene.
NEW LINE<table><tr><td>[[Image:UrbanCanyon6.png|thumb|left|640px|The received power coverage map of the random city scene with a highly directional dipole array transmitter.]]</td></tr></table>
* Ray Number* θ and φ Angles By Default, [[EM.Cube]] always visualizes the 3D radiation patterns at the origin of Arrival coordinates, i.e. at (0, 0, 0). This is because that radiation pattern data are computed in deg* &the standard spherical coordinate system centered at (0, 0, 0). The theta; and φ Angles components of Departure 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 deg* Delay 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 nsec* Real(E<sup>V</sup>) & Imag(E<sup>V</sup>)* Real(E<sup>H</sup>) & Imag(E<sup>H</sup>)* Real('''Ethe project workspace.e<sub>R</sub>''') & Imag('''EIt also allows you to scale up or scale down the pattern visualization with respect to the background scene.e<sub>R</sub>''')* Power
The angles of arrival are In the θ and φ angles of a received ray measured in degrees and are referenced in example shown above, the spherical coordinate systems centered at imported pattern data file is called "Dipole_Array1.RAD". Therefore, the location label of the receiverradiation pattern observable is chosen to be "Dipole_Array1". The angles of departure for a received ray are the θ and phi angle increments are both 1&phideg; angles of the originating transmitter ray, measured in degrees and referenced in the spherical coordinate systems centered at the location of the active transmitter, which eventually arrives at the receiverthis case. The total time delay is measured in nanoseconds between t = 0 nsec radiation pattern has been elevated by 10m to be positioned at the time location of launch from the transmitter location till being received at the receiver location. The last four columns show the real and imaginary parts a scaling factor of the received electric fields with vertical and horizontal polarizations, respectively0. 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 file3 has been used.
<table><tr><td>[[FileImage:prop_run8_tnUrbanCanyon8.png|800pxthumb|left|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>
FigureThere is an important catch to remember here. When you define a radiation pattern observable for 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 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). Â <table><tr><td>[[Image: A typical UrbanCanyon9.png|thumb|left|640px|EM.Terrano's Run Simulation dialog.]]</td></tr></table>Â == Using EM.Terrano as an Asymptotic Field Solver ==Â Like every other electromagnetic solver, EM.Terrano's SBR output ray tracer requires an excitation source and one or more observables for the generation of simulation data. EM.Terrano offers several types of sources and observables for a SBR simulation. You already learned about the transmitter set as a source and the receiver set as an observable. You can mix and match different source types and observable types depending on the requirements of your modeling problem. Â The available source types in EM.Terrano are:Â {| class="wikitable"|-! scope="col"| Icon! scope="col"| Source Type! scope="col"| Applications! scope="col"| Restrictions|-| style="width:30px;" | [[File:transmitter_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|}Â Click on each type to learn more about it in the [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types]]. Â The available observables types in [[EM.Terrano]] are:Â {| class="wikitable"|-! scope="col"| Icon! scope="col"| Source Type! scope="col"| Applications! scope="col"| Restrictions|-| style="width:30px;" | [[File:receiver_icon.png]]| style="width:150px;" | [[Glossary of EM.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 be associated with a base location point set|-| style="width:30px;" | [[File:Distr Rx icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Distributed Receiver Set | Distributed Receiver Set]]| style="width:250px;" | Computing received power at a receiver characterized by Huygens surface data| style="width:250px;" | None, stand-alone source imported from a Huygens surface data file|-| style="width:30px;" | [[File:fieldsensor_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Near-Field Sensor Observable | Near-Field Sensor]]| style="width:250px;" | Generating electric and magnetic field distribution maps| style="width:250px;" | None, stand-alone observable|-| style="width:30px;" | [[File:farfield_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Far-Field Radiation Pattern Observable | Far-Field Radiation Pattern]]| style="width:250px;" | Computing the effective radiation pattern of a radiator in the presence of a large scattering scene | style="width:250px;" | None, stand-alone observable|-| style="width:30px;" | [[File:huyg_surf_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's 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|}Â Click on each type to learn more about it in the [[Glossary of EM.Cube'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. Â {{Note| Computing radiation patterns using EM.Terrano's SBR solver typically takes much longer computation times than using [[EM.Cube]]'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 free space at 1GHz.]] </td></tr></table>
=== Statistical Analysis of Propagation Scene ===
[[Image:PROP12A.png|thumb|400px|EM.Terrano's Simulation Run dialog showing frequency sweep as the simulation mode along with statistical analysis.]]
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 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.
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 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 Coverage Mapsreceived 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.
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<td> [[Image:prop_run21_tnPROP MAN12.png|thumb|400pxleft|The mean coverage map at the end of a 480px|EM.Terrano's simulation run dialog showing frequency sweepas the simulation mode along with statistical analysis.]] </td><td> [[Image:prop_run22_tn.png|thumb|400px|The standard deviation coverage map at the end of a frequency sweep.]] </td>
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<ptable> <tr><td> [[Image:UrbanCanyon4.png|thumb|left|640px|The mean coverage map at the end of a frequency sweep.]] </ptd></tr><tr><td>[[Image:TOPUrbanCanyon5.png|40pxthumb|left|640px|The standard deviation coverage map at the end of a frequency sweep.]] </td></tr></table>Â <br />Â <hr>Â [[Image:Top_icon.png|30px]] '''[[EM.Terrano#An_EM.Terrano_Primer Product_Overview | Back to the Top of the Page]]'''Â [[Image:Tutorial_icon.png|30px]] '''[[EM.Cube#EM.Terrano_Documentation | EM.Terrano Tutorial Gateway]]'''
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