[[Image:Splash-prop.jpg|right|900px720px]]<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:Info_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:Info_iconManhattan1.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:Info_iconEM.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 '''[[SBR_Method#Freespace-Space_Wave_Propagation | Freepartitioning data structure for organizing points in a k-Space Propagation Channel]]'''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:Info_icon.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:Info_icon.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 dialog"Random City" and "Basic Link" wizards. It consists of 25 cubic brick buildings, one transmitter and a large two-dimensional array of receivers.]][[Image:PROP4.png|thumb|400px|EM.Terrano's Global Ground Settings dialog.]]</td></tr></table>
=== Why Do You Need a Finite Computational Domain? Organizing the Propagation Scene by Block Groups ===
The SBR simulation engine requires a finite computational domain for ray terminationIn EM. All Terrano, all the stray rays that emanate from a source inside this finite domain and hit its boundaries are terminated during the simulation process. Such rays exit the computational domain and travel to the infinity, geometric objects associated with no chance of ever reaching any receiver in the various scene. When you define a propagation scene with various elements like buildings, walls, terrain, etc., a dynamic domain is automatically established surfaces and displayed base location points are grouped together as blocks based on their common type. All the objects listed under a green wireframe box that surrounds particular group in the entire scenenavigation tree share the same color, texture and material properties. Every time you create Once a new objectblock group has been created in the navigation tree, it becomes the domain box "Active" group of the project workspace, which is automatically adjusted and extended to enclose all always displayed in bold letters. You can draw new objects under the objects active node. Any block group can be made active by right-clicking on its name in the scenenavigation tree and selecting the '''Activate''' item of the contextual menu.
To change the ray domain settings, follow the procedure below<table><tr><td> [[Image:PROP MAN1.png|thumb|left|480px|EM.Terrano's navigation tree.]]</td></tr></table>
* Open It is recommended that you first create block groups, and then draw new objects under the Ray Domain Settings Dialog by clicking the '''Domain''' [[File:image025active block group.jpg]] button of the '''Simulate Toolbar'''However, or by selecting '''Menu > Simulate > Computational Domain > Settingsif you start a new EM...'''Terrano project from scratch, or by right-clicking on the '''Ray Domain''' item of 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 and selecting '''Domain Settingsto hold your new CAD object...''' You can always change the properties of a block group later by accessing its property dialog from the contextual menu, 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 delete a block group with all 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 openits objects at any time.
=== Understanding {{Note|You can only import external CAD models (STEP, IGES, STL, DEM, etc.) only to the Global Ground ===CubeCAD module. You can then transfer the imported objects from CubeCAD to EM.Terrano.}}
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> Moving Objects Among Different Block Groups == 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 You can use move any geometric object or a selection of objects from one block group to another. You can also transfer objects among [[EM.TerranoCube]]'s '''Empirical Soil Model''' different modules. For example, you often need to define the material properties move imported CAD models of the global groundterrain or buildings from CubeCAD to EM. This model requires a number of [[parameters]]: Temperature 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 °rarr;CModule Name → Object Group</b> from the contextual menu. For example, and Volumetric Water Contentif you want to move a selected object to a block group called "Terrain_1" in EM.Terrano, Sand Content and Clay Content all then you have to select the menu item '''Move To → EM.Terrano → Terrain_1''' as percentageshown 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.
{{Note<table><tr><td> [[Image:PROP MAN3.png|thumb|left|720px|To Moving the terrain model a free-space propagation scene, you have of Mount Whitney originally imported from an external digital elevation map (DEM) file to disable 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 default global groundproject workspace under a terrain group called "Terrain_1".}}]]</td></tr></table>
=== Buildings, Adjustment of Block Elevation on Underlying Terrain & Obstructing Blocks Surfaces ===
ImpenetrableIn EM.Terrano, penetrable buildings and terrain surfaces and penetrable volumes represent buildings, blocks or all other geometric objects that obstruct are initially drawn on the propagation XY plane. In other words, the Z-coordinates of electromagnetic waves the local coordinate system (raysLCS) in the free space. What differentiates them is the types of physical phenomena that all blocks are used set to model their interaction with the impinging rayszero until you change them. The field intensitySince the global ground is located a z = 0, phase and power of your buildings are seated on the reflected and transmitted rays depend ground. When your propagation scene has an irregular terrain, you would want to place your buildings on the material properties surface of the obstructing surfaceterrain and not buried under it. The specular surface This can be modeled as a simple homogeneous dielectric half-space or done automatically as part of the definition of the block group. Open the property dialog of a multilayer structureblock group and check the box labeled '''Adjust Block to Terrain Elevation'''. In All the objects belonging to that respect, block are automatically elevated in the buildings, walls, Z direction such that their bases sit on the surface of their underlying terrain or even . In effect, the LCS of each of these individual objects is translated along the global ground all behave in a similar way:Z-axis by the amount of the Z-elevation of the terrain object at the location of the LCS.
* They terminate an impinging ray {{Note| You have to make sure that the resolution of your terrain, its variation scale and replace it with one or more new raysbuilding dimensions are all comparable.* They represent Otherwise, on a specular interface between two media of different material compositions for calculating the reflectionrapidly varying high-resolution terrain, transmission you will have buildings whose bottoms touch the terrain only at a few points and possibly diffraction coefficientsparts of them hang in the air.}}
<table><tr><td> [[EMImage:PROP MAN5.Terrano]] has generalized png|thumb|left|480px|The property dialog of impenetrable surface showing the concept of '''Block''' as any object that obstructs and affects radio wave propagationterrain elevation adjustment box checked. The following table summarized the [[Block Types|block types]]: </td></tr></table>
{| class="wikitable"<table>|-<tr>! scope="col"| Block Type<td> ! scope="col"[[Image:PROP MAN6.png|Physical Effects! scope="col"thumb|Legitimate Object Typesleft|-360px| Impenetrable SurfaceA set of buildings on an undulating terrain without elevation adjustment.]]| Reflection, Diffraction</td>| All solid & surface CAD objects<td>[[Image:PROP MAN7.png|-thumb| Penetrable Volumeleft| Reflection, Diffraction, Material Medium Transmission360px| All solid CAD objectsThe set of buildings on the undulating terrain after elevation adjustment.]]|-</td>| Penetrable Surface</tr>| Reflection, Diffraction, Thin-Wall Transmission| All solid & surface CAD objects|-| Terrain Surface| Reflection| Specially created tessellated objects only |}</table>
[[Image:Info_icon== EM.png|40px]] Click here to learn more about Terrano'''[[Block Types]]'''.s Ray Domain & Global Environment ==
[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Block_Types#Using_EM.Terrano.27s_Terrain_Generator | Using Terrain Generator]]'''.=== Why Do You Need a Finite Computational Domain? ===
[[Image:prop_manual-12_tnThe SBR simulation engine requires a finite computational domain for ray termination.png|thumb|500px|An imported external All the stray rays that emanate from a source inside this finite domain and hit its boundaries are terminated during the simulation process. Such rays exit the computational domain and travel to the infinity, with no chance of ever reaching any receiver in the scene. When you define a propagation scene with various elements like buildings, walls, terrain model, etc., a dynamic domain is automatically established and displayed as a green wireframe box that surrounds the entire scene. Every time you create a new object, the domain box is automatically adjusted and extended to enclose all the objects in the scene.]]
=== Moving Objects among Block Groups ===To change the ray domain settings, follow the procedure below:
You can move one or more selected objects at a time among different block groups* Open the Ray Domain Settings Dialog by clicking the '''Domain''' [[File:image025. The objects can be selected either in jpg]] button of the project workspace'''Simulate Toolbar''', or their names can be selected from the navigation treeby selecting '''Menu > Simulate > Computational Domain > Settings. Right click ..''', or by right-clicking on the highlighted selection '''Ray Domain''' item of the navigation tree and select selecting '''Move To > Propagation >Domain Settings...''' from the contextual menu, or simply using the keyboard shortcut {{key|Ctrl+A}}. This opens up another sub-menu with a list * The size of all the available block groups already defined Ray domain is specified in your EM.Terrano project. Select terms of six '''Offset''' parameters along the desired block node±X, ±Y and ±Z directions. The default value of all the selected objects will move to that block groupthese six offset parameters is 10 project units. In Change these values as you like.* You can also change the case color of a multiple selection from the navigation tree domain box using the keyboard's {{key|ShiftColor}} key or {{key|Ctrl}} keybutton.* After changing the settings, make sure that you continue to hold use the keyboard's {{key|ShiftApply}} key or {{key|Ctrl}} key down button to make the changes effective while selecting the destination block group's name from the contextual menudialog is still open.
In a similar way, you can move one or more objects from an EM.Terrano block group to one of <table><tr><td> [[Image:PROP15.png|thumb|left|480px|EM.Cube]]Terrano's other modulesdomain settings dialog. In this case, the sub-[[menus]] of the '''Move To </td></tr></table>''' 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.
{{Note|Except for external terrain models, you can import other external objects (STEP, IGES, STL, etc.) only to '''[[CubeCAD]]'''. You need to move === Understanding the imported objects form [[CubeCAD]] to EM.Terrano as described above.}}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 = Defining Base Point Sets =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.
[[File:PROP1.png|thumb|300px|[[Propagation Module]]'s Base Set dialog]]Alternatively, you can use EM.Terrano uses 's ''Point'Empirical Soil Model''' objects to position transmitters and receiver in the propagation scene. Points are regular CAD objects that can be moved around (translated) in the project workspace. The point objects that are used to represent the transmitters and receivers are grouped together and organized as '''Base Sets''' in define the "Physical Structure" section material properties of the navigation treeglobal ground. When you move the point objects or change their coordinates, all of their associated transmitters or receivers immediately follow them to the new location. For example, you can define This model requires a grid number of receivers using a base set that is made up of a uniformly spaced array of points and spread them parameters: Temperature in your scene. You can easily interchange the role of transmitters °C, 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 Volumetric Water Content, Sand Content and adjustment of their elevationClay Content all as percentage.
{{Note|To create model a new base setfree-space propagation scene, follow these steps;you have to disable EM.Terrano's default global ground.}}
* Right-click on the '''Base Sets''' item of navigation tree and select '''Insert Base Set.<table><tr><td> [[Image:Global environ.png|thumb|left|720px|EM.Terrano''' A s Global Environment Settings dialog for setting up the Base Set properties opens up.]]* Enter a name for the base set and change the default blue color if you wish. It is useful to differentiate the base sets associated with transmitters and receivers by their color.</td>* Click the {{key|OK}} button to close the Base Set Dialog.</tr></table>
Once a base set node has been added to the navigation tree, it becomes the active node for drawing new objects. Under base sets, you can only draw point objects. All other object creation tools are disabled. A point is initially drawn on the XY plane. Make sure to change the Z-coordinate of your point, otherwise, your radiator will fall on the global ground at z = 0. You can also create arrays of base points under the same base set. This is particularly useful for setting up receiver grids to compute coverage maps. Simply select a point object and click the '''Array Tool''' of '''Tools Toolbar''' or use the keyboard shortcut = Defining Point Transmitters "amp;A". Enter values Point Receivers for the X, Y or Z spacing as well as the number of elements along these three directions in the Array Dialog. In most propagation scenes you are interested in 2D horizontal arrays along a fixed Z coordinate (parallel to the XY plane).Your Propagation Scene ==
== Defining Sources = The Nature of Transmitters & Observables for Your SBR Simulation Receivers ===
Like every other electromagnetic solver, In EM.Terrano's SBR ray tracer requires an excitation source , transmitters and one or more observables receivers are indeed point radiators used for generation transmitting and receiving signals at different locations of simulation datathe propagation scene. EMFrom a geometric point of view, both transmitters and receivers are represented by point objects or point arrays.Terrano offers several types These are grouped as base locations in the "Physical Structure" section of sources the navigation tree. As radiators, transmitters and observables for receivers are defined by a SBR simulationradiator type with a certain far-field radiation pattern. You can mix and match different Consistent with [[EM.Cube]]'s other computational modules, transmitters are categorizes as an excitation source types and , while receivers are categorized as a project observable types depending . In other words, a transmitter is used to generate electromagnetic waves that propagate in the physical scene. A receiver, on the requirements of your modeling problemother hand, is used to compute the received fields and received signal power or signal-to-noise ratio (SNR). The available source types 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.
* [[#Defining Transmitter Sets | Transmitter]]* [[Asymptotic_Field_Solver | Hertzian Dipole]]EM.Terrano provides three radiator types for point transmitter sets:
The available observables types are :#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
* [[#Defining Receiver Sets | Receiver]]* Field Sensor* Far Field Radiation Pattern* Huygens SurfaceEM.Terrano also provides three radiator types for point receiver sets:
A short #Half-wave dipole source is oriented along one of the simplest type of excitation for your propagation scene. A short dipole has an almost "omnithree principal axes#Polarization-directional" radiation pattern, and is the closest thing to an matched isotropic radiator. EM.Terrano does not provide a theoretical/hypothetical isotropic transmitter because its SBR solver is fully polarimetric and requires a real physical radiator for ray generation. A transmitter is a more sophisticated source that requires an #User defined (arbitrary) antenna with imported far-field radiation pattern file with a '''.RAD''' file extension.
{{Note| In order to define a The default transmitter, you need to import a radiation pattern file from one of [[EMand receiver radiator types are both vertical (Z-directed) half-wave dipoles.Cube]]'s other computational modules.}}
Of the above list of EM.Terrano's observables types, receivers There are the ones you would typically use for your propagation scenes. Unlike three different ways to define a transmitter, set or a receiver by default does not require an imported radiation pattern file. A default receiver is assumed to be polarization-matched to the incoming ray. The other three observable types, field sensor, far fields and Huygens surface are primarily used in applications that utilize EM.Terrano as an [[Asymptotic Field Solver|asymptotic field solver]]. set:
[[Image:Info_icon.png|40px]] Click here to learn more about *By defining field sensor observables for '''[[Data_Visualization_and_Processing#Visualizing_3D_Near-Field_Maps | Visualizing 3D Near-Field Maps]]'''.point objects or 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, emag_rx, emag_tx_array, emag_rx_array, emag_tx_line and emag_rx_line*Using the "Basic Link" wizard
[[Image:Info_icon.png|40px]] Click here to learn more about computing radiation patterns using '''[[Data_Visualization_and_Processing#Far-Field_Observables | Far-Field Observables]]'''.=== Defining a Point Transmitter Set in the Formal Way ===
[[Image:Info_iconTransmitters act as sources in a propagation scene.png|40px]] Click here to learn more about '''[[Hybrid_Modeling_using_Multiple_Simulation_Engines#Generating_Huygens_Surface_Data | Generating Huygens Surface Data]]'''A transmitter is a point radiator with a fully polarimetric radiation pattern defined over the entire 3D space in the standard spherical coordinate system.EM.Terrano gives you three options for the radiator associated with a point transmitter:
== Defining Transmitters & Receivers for Your Propagation Scene ==* Half-wave dipole* Orthogonally polarized isotropic radiators* User defined antenna pattern
=== Defining Transmitter Sets ===By default, EM.Terrano assumes that your transmitter is a vertically polarized (Z-directed) resonant half-wave dipole antenna. This antenna has an almost omni-directional radiation pattern in all azimuth directions. It also has radiation nulls along the axis of the dipole. You can change the direction of the dipole and orient it along the X or Y axes using the provided drop-down list. The second choice of two orthogonally polarized isotropic radiators is an abstract source that is used for polarimetric channel characterization as will be discussed later.
A transmitter is a point You can override the default radiator option and select any other kind of antenna with a fully defined polarimetric more complicated radiation pattern over the entire 3D space in the spherical coordinate system. For this purpose, you have to import a radiation pattern data file to EM.Terrano. You can model a any radiating structure using [[EM.Tempo|Cube]]'s other computational modules, [[EM.TEmpoTempo]], [[EM.Picasso]], [[EM.Libera]] or [[EM.Illumina]] , and generate a 3D radiation pattern data file for it. These The far-field radiation patter data are stored in a specially formatted file with a "'''.RAD'''" file extension. It This file contains columns of spherical φ and θ angles as well as the real and imaginary parts of the complex-valued far -zone electric field components '''E<sub>θ</sub>''' and '''E<sub>φ</sub>'''. The θ- and φ-components of the far-zone electric field determine the polarization of the transmitting radiator.
[[Image:Info_icon{{Note|By default, EM.png|40px]] Click here to learn more about the format of '''[[Data_Visualization_and_Processing#Far_Field_Data_Files | Radiation Pattern Files]]'''Terrano assumes a vertical half-wave dipole radiator for your point transmitter set.}}
To define a A transmitter source in EM.Terrano, first you need set always needs to have at least be associated with an existing base location set with one '''Base Point''' or more point objects in your the project workspace. Follow the procedure below:Therefore, you cannot define a transmitter for your scene before drawing a point object under a base location set.
* Right-click on the '''Transmitters''' item of the navigation tree and select '''Insert New Transmitter Set[[Image:Info_icon...''' from the contextual menu. This opens of the Transmitter Set dialog.* Choose png|40px]] Click here to learn how to define a name and color for your transmitter set. * From the dropdown list labeled '''Associated Base Point Set''', select the desired set.* In the "Custom Pattern [[Parameters]]"Glossary_of_EM.Cube%27s_Materials, click the {{key_Sources,_Devices_%26_Other_Physical_Object_Types#Point_Transmitter_Set |Import Pattern}} button to set the path for the radiation data file. This opens up the standard [[WindowsPoint Transmitter Set]] Open dialog, with the default file type or extension set to '''.RAD'''. Browse your folders to find the right data file. * You can also rotate the imported pattern about the three principal axes. Enter the rotation angles other than the zero default values, if necessary.* Click the {{key|OK}} button of the dialog to close it.
A new transmitter set entry is added in the '''Transmitters''' section of the navigation tree<table><tr><td> [[Image:Terrano L1 Fig11. After defining a png|thumb|left|480px|The point transmitter set, the base points associated with it change their color to the transmitter color, which is red by default. In the Transmitter Set definition dialog, you can also set the '''Baseband Power''' of your transmitter in Watts and its '''Phase''' in degrees. There is a check box labeled '''Custom Power''', which is checked by default. In that case, the power and phase boxes are enabled and you can change the default 1W power and 0° phase values as you wish. [[EM.Cube]]'s ".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 "Custom Power" check box is unchecked, EM.Terrano will use the total radiated power value of the radiation file for SBR calculations. </td></tr></table>
EM.Terrano allows Once you to define a basic new transmitter set, its name is added in the '''Heterodyne Transmitter ChainTransmitters'''. Click the {{key|Transmitter Chain}} button section of the Transmitter Set dialog to open the Transmitter Chain dialognavigation tree. As shown in The color of all the figure below, you can specify base points associated with the characteristics of the baseband/IF amplifiernewly defined transmitter set changes, mixer and power amplifier an additional little ball with the transmitter color (PAred by default) including stage gains and impedance mismatch factors (IMF) as well as appears at the characteristics location of the transmission line segment that connects the PA to the antennaeach associated base point. Note that You can open the transmitting antenna characteristics are automatically filled from using contents property dialog of the radiation filetransmitter set and modify a number of parameters including the '''Source Power''' in Watts and the broadcast signal '''Phase''' in degrees. The default transmitter Chain dialog power level is 1W or 30dBm. There is also calculates a check box labeled '''Use Custom Input Power''', which is checked by default. In that case, the power and reports phase boxes are enabled and you can change the default 1W power and 0° phase values as you wish. [[EM.Cube]]'s "Total Transmitter Chain Gain.RAD" radiation pattern files usually contain the value of "Total Radiated Power" in their file header. This quantity is calculated based on your inputthe particular excitation mechanism that was used to generate the pattern file in the original [[EM.Cube]] module. When you close this dialog and return to the Transmitter Set dialog"Use Custom Input Power" check box is unchecked, you EM.Terrano will see use the calculated total radiated power value of the Effective Isotropic Radiated Power (EIRP) radiation file for the SBR simulation. Â {{Note|In order to modify any of your the transmitter in dBmset's parameters, first you need to select the "User Defined Antenna" option, even if you want to keep the vertical half-wave dipole as your radiator. }}
{{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:PROP20(1)NewTxProp.png|thumb|400pxleft|EM.Terrano's Transmitter 720px|The property dialog with of a user defined pattern selectedpoint transmitter set.]] </td><td> [[File:PROP20A.png|thumb|600px|EM.Terrano's Transmitter Chain dialog.]] </td>
</tr>
</table>
=== Defining Receiver Sets ===Your transmitter in EM.Teranno is indeed more sophisticated than a simple radiator. It consists of a basic "Transmitter Chain" that contains a voltage source with a series source resistance, 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's property dialog allows you to define the basic transmitter chain. Click the {{key|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.
{{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:PROP21(1)NewTxChain.png|thumb|400pxleft|720px|EM.Terrano's preliminary Receiver point transmitter chain dialog.]] </td>Receivers act as observables in a propagation scene. The objective of a SBR simulation is to calculate the far-zone electric fields and the total received power at the location of a receiver. 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. </tr></table>
To define === Defining a receiver observable Point Receiver Set in EM.Terrano, follow the procedure below:Formal Way ===
* Right-click on the '''Receivers''' item act as observables in a propagation scene. The objective of a SBR simulation is to calculate the navigation tree far-zone electric fields and select '''Insert New Receiver Set...''' from the contextual menu. This opens of total received power at the preliminary Receiver Set dialog.* Choose location of a name and for your receiver set. * From You need to define at least one receiver in the dropdown list labeled '''Associated Base scene before you can run a SBR simulation. Similar to a transmitter, a receiver is a point Set'''radiator, select the desired settoo.* Click the {{key|OK}} button of the dialog to close itEM. Terrano gives you three options for the radiator associated with a point receiver set:
A new receiver set entry is added in the '''Receivers''' section of the navigation tree. After defining a receiver set, the base points associated with it change their color to the receiver color, which is yellow by default. The first element of the set is represented by a larger ball of the same color indicating that it is the selected receiver in the scene. * Half-wave dipole* Polarization matched isotropic radiator* User defined antenna pattern
The Receiver Set Dialog By default, EM.Terrano assumes that your receiver is also used to access individual receivers of the set for data visualization at the end of a simulationvertically polarized (Z-directed) resonant half-wave dipole antenna. At You can change the end direction of an SBR simulation, the button labeled "Show Ray Data" becomes enableddipole and orient it along the X or Y axes using the provided drop-down list. An isotropic radiator has a perfect omni-directional radiation pattern in all azimuth and elevation directions. Clicking this button opens An isotropic radiator doesn't exist physically in the Ray Data Dialogreal world, where you but it can see be used simply as a list of all point in space to compute the received rays at the selected receiver and their computed characteristicselectric field.
{{Note| 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 receivers, by default, are defined as isotropic or polarization-matched radiatorssimilar to the case of a transmitter set.}}
If you want directional radiators for your receiver set, you need to open the Receiver dialog by right-clicking on the receiver set's name in the navigation tree and opening its property dialog from the contextual menu. In the "Radiator Properties" section of this dialog, select the '''User Defined''' radio button. Similar to the case of transmitter set, you can import a '''.RAD''' radiation pattern file using the {{keyNote|Import Pattern}} button. You can also rotate the imported radiation pattern by setting '''Rotation Angles''' different than the By default zero values. , EM.Terrano allows you to define assumes a basic '''Heterodyne Receiver Chain'''. Click the {{key|Receiver Chain}} button of the Receiver Set dialog to open the Receiver Chain dialog. As shown in the figure below, you can specify the characteristics of the Lowvertical half-Noise Amplifier (LNA), mixer and baseband/IF amplifier including stage gains and impedance mismatch factors (IMF) as well as the characteristics of the transmission line segment that connects the antenna to the LNA. Note that the receiving antenna characteristics are automatically filled from using contents of the radiation file. You have to enter values wave dipole radiator for antenna's '''Brightness Temperature''' as well as the temperature of the transmission line and the your point receiver's ambient temperature. The effective '''Receiver Bandwidth''' is assumed to be 100MHz, which you can change for the purpose of noise calculations. You also need to enter values for the '''Noise Figure''' of various active devices in the receiver chain. The Receive Chain dialog calculates and reports the "Noise Power" and "Total Receiver Chain Gain" based on your inputset. }}
In the Receiver Set dialogSimilar to transmitter sets, there is you define a dropdown list labeled "Selected Receiver", which contains a list of all receiver set by associating it with an existing base location set with one or more point objects in the project workspace. All the individual receivers belonging to the same receiver set. At have the end same radiator type. A typical propagation scene contains one or few transmitters but usually a large number of an SBR simulationreceivers. To generate a wireless coverage map, the receiver power and signal-noise ratio (SNR) you need to define an array of the selected receiver are calculated and reported in dBm and dB, respectivelypoints as your base location set. The {{key  [[Image:Info_icon.png|Show Ray Data}} button also allows you 40px]] Click here to see the details of all the received rays by the selected receiverlearn how to define a '''[[Glossary_of_EM.Cube%27s_Simulation_Observables_%26_Graph_Types#Point_Receiver_Set | Point Receiver Set]]'''.
<table>
<tr>
<td> [[FileImage:PROP22Terrano L1 Fig12.png|thumb|400pxleft|EM.Terrano's Receiver dialog with an isotropic radiator selected.]] </td><td> [[File:PROP22A.png480px|thumb|600px|EM.Terrano's Receiver Chain The point receiver set definition dialog.]] </td>
</tr>
</table>
=== A Note on the Rotation of Antenna Radiation Patterns ===Â EM.Terrano's Transmitter Set dialog and Receiver Set dialog both allow Once you to rotate an imported radiation pattern. In that casedefine a new receiver set, you need its name is added to specify the '''RotationReceivers''' angles in degrees about section of the X-, Y- and Z-axesnavigation tree. It is important to note that these rotations are performed sequentially and in The color of all the following order: first a rotation about base points associated with the X-axis, then a rotation about the Y-axisnewly defined receiver set changes, and finally a rotation about the Z-axis. In addition, all the rotations are performed an additional little ball with respect to the "rotated" local coordinate systems receiver color (LCSyellow by default)appears at the location of each associated base point. In other words, You can open the first rotation with respect to property dialog of 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 performed with respect to the new Y<sup>′</sup>-axis receiver set and transforms the X<sup>′</sup>Y<sup>′</sup>Z<sup>′</sup> LCS to modify a 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 rotationsnumber of parameters.
<table>
<tr>
<td> [[File:PROP22BNewRxProp.png|thumb|200pxleft|720px|The local coordinate system property dialog of a linear dipole antennapoint receiver set.]] </td><td> [[File:PROP22C.png|thumb|370px|Rotating the dipole antenna by +90° about the local Y-axis.]] </td><td> [[File:PROP22D.png|thumb|480px|Rotating the dipole antenna by +90° about the local X-axis and then by -45° by the local Y-axis.]] </td>
</tr>
</table>
=== Adjustment In the Receiver Set dialog, there is a drop-down list labeled '''Selected Element''', which contains a list of Tx/Rx Elevation above all the individual receivers belonging to the receiver set. At the end of an SBR simulation, the button labeled {{key|Show Ray Data}} becomes enabled. Clicking this button opens the Ray Data dialog, where you can see a Terrain Surface ===list of all the received rays at the selected receiver and their computed characteristics.
When If you choose the "user defined antenna" option for your transmitters or receivers are located above receiver set, it indeed consists of a flat terrain like basic "Receiver Chain" that contains a receive antenna connected via a segment of transmission line to the global ground, their Zlow-coordinates are equal noise amplifier (LNA) that is terminated in a matched load. The receiver set's property dialog allows you to their height above define the ground, as basic receiver chain. Click the terrain elevation is fixed and equal {{key|Receiver Chain}} button of the Receiver Set dialog to zero everywhereopen the receiver chain dialog. In many propagation modeling problems, your transmitters and receivers may be located above an irregular terrain with varying elevation across As shown in the scene. In that casefigure below, you may want to place your transmitters or receivers at a certain height above can specify the underlying ground. The Z-coordinate characteristics of a transmitter or receiver is now the sum of the terrain elevation at the base point LNA such as its gain and noise figure in dB as well as the specified height. EM.Terrano gives you characteristics of the option to adjust transmission line segment that connects the transmitter and receiver sets antenna to the terrain elevationLNA. This is done for individual transmitter sets and individual receiver sets. At Note that the top receiving antenna characteristics are automatically filled from using contents of the Transmitter Dialog there is a check box labeled "radiation file. You have to enter values for antenna's ''Adjust Tx Sets to Terrain Elevation'Brightness Temperature''". Similarly, at ' as well as the top temperature of the Receiver Dialog there is a check box labeled "transmission line and the receiver's ambient temperature. The effective ''Adjust Rx Sets to Terrain Elevation'Receiver Bandwidth''". These boxes are unchecked by default. As a result' is assumed to be 100MHz, your transmitter sets or receiver sets coincide with their associated base points in which you can change for the project workspacepurpose of noise calculations. If you check these boxes The Receive Chain dialog calculates and place a transmitter set or a receiver set above an irregular terrain, reports the transmitters or receivers are elevated from "Noise Power" and "Total Receiver Chain Gain" based on your input. At the location end of their associated base points by an SBR simulation, the amount receiver power and signal-noise ratio (SNR) of terrain elevation as can be seen in the figure below. Â To better understand why there selected receiver are two separate sets of points calculated and they are reported in the scenereceiver set dialog in dBm and dB, note that a point array (CAD object) is used to create a uniformly spaced base setrespectively. The array object always preserves its grid topology as you move it around You can examine the scene. However, properties of all the transmitters or individual receivers associated with this point array object are elevated above the irregular terrain and no longer follow a strictly uniform grid. If you move all the base individual rays received by each receiver in your receiver set from its original position to a new location, using the base points' topology will stay intact, while the associated transmitters or receivers will be redistributed above the terrain based on their new elevations"Selected Element" drop-down list.
<table>
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<td> [[ImageFile:prop_txrx1_tnNewRxChain.png|thumb|400pxleft|Transmitter (red) and receivers (yellow) adjusted above an uneven terrain surface720px|EM.]] </td><td> [[Image:prop_txrx2_tn.png|thumb|400px|The underlying base Terrano's point sets (blue and orange dots) associated with the adjusted transmitters and receivers on the terrainreceiver chain dialog.]] </td>
</tr>
</table>
== Using = Modulation Waveform and Detection === EM.Terrano allows you to define a digital modulation scheme for your communication link. There are currently 17 waveforms to choose from in the receiver set property dialog: *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 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 bandwidth in Hz, and C is the channel capacity (maximum data rate) expressed in bits/s. The spectral efficiency of the channel is defined as an Asymptotic Field Solver  <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 noise power spectral density. It is a measure 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 relationship between the bit error rate and E<sub>b</sub>/N<sub>0</sub> depends on the modulation scheme and detection type (coherent vs. non-coherent). For example, for coherent QPSK modulation, one can write: <math> P_b = 0.5 \; \text{erfc} \left( \sqrt{ \frac{E_b}{N_0} } \right) </math> where P<sub>b</sub> is the bit error rate and erfc(x) is the complementary error function: <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 receiver pair. If you check the box labeled '''Generate Connectivity Map''' in the receiver set 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 transmitter set or a new receiver set, EM.Terrano assigns a vertically polarized half-wave dipole radiator to the set by default. The radiation pattern of this native dipole radiators is calculated using well-know expressions that are derived based on certain assumptions and approximations. For example, the far-zone electric field of a vertically-polarized dipole antenna can be expressed as:  <math> 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>
The simplest SBR simulation can be performed using a short dipole source with a specified field sensor plane. As an asymptotic EM solver<math> E_\phi(\theta, EM.Terrano then computes the electric and magnetic fields radiated by your dipole source 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.\phi) \approx 0 </math>
[[Image:Info_icon.png|40px]] Click here to learn more about using EM.Terrano as an '''[[Asymptotic Field Solver]]'''where k<sub>0</sub> = 2π/λ<sub>0</sub> is the free-space wavenumber, λ<sub>0</sub> is the free-space wavelength, η<sub>0</sub> = 120π Ω is the free-space intrinsic impedance, I<sub>0</sub> is the current on the dipole, and L is the length of the dipole.
=== Defining a Hertzian Dipole Source ===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[[File:PROP18\frac{\text{cos} \left(1\frac{k_0 L}{2} \text{cos} \theta \right).png|thumb|350px|EM.Terrano's Short Dipole Source dialog.]]A short dipole is the simplest way of exciting a structure in [[EM.Terrano]]. It is also the closest thing to an omnidirectional radiator. The direction or orientation of the short dipole determines its polarization. Note that [[EM.Terrano]- \text{cos} \left( \frac{k_0 L}{2} \right) }{\text{sin}\theta} \right] does not offer an isotropic radiator as a source type because it is a polarimetric ray tracer. A short dipole source acts like an infinitesimally small ideal current source. ^2 </math>
To define a short dipole source, follow these steps:with
* Right click on the '''Short Dipoles''' item in the '''Sources''' section of the Navigation Tree and select '''Insert New Source...''' from the contextual menu. The Short Dipole dialog opens up.* In the '''Source Location''' section of the dialog, you can set the coordinate of the center of the short dipole. By default, the source is placed at the origin of the world coordinate system at <math> F_1(0,0,0x). You can type in new coordinates or use the spin buttons to move the dipole up from the default global ground.* In the '''Source Properties''' section, you can specify the '''Amplitude''' in Amperes, the '''Phase''' in degrees as well as the '''Length''' of the dipole in project units.* In the '''Direction Unit Vector''' section, you can specify the orientation of the short dipole by setting values for the components '''uX''', '''uY''', and '''uZ''' of the dipole's unit vector. The default values correspond to a vertical = \gamma + \text{ln}(Zx) -directedC_i(x) short dipole. The dialog normalizes the vector components upon closure even if your component values do not satisfy a unit magnitude. </math>
The radiation resistance of a short dipole of length ''dl'' is given by:<math> F_2(x) = \frac{1}{2} \text{sin}(x) \left[ S_i(2x) - 2S_i(x) \right] </math>
:<math> R_r F_3(x) = 80\pi^2 \left( \frac{dl1}{\lambda_02} \righttext{cos}(x)^\left[ \gamma + \text{ln}(x/2 ) + C_i(2x) - 2C_i(x) \right] </math>
The radiated power of a short dipole carrying a current I<sub>0</sub> is then given by:
:where γ = 0.5772 is the Euler-Mascheroni constant, and C<mathsub>i</sub> P_{rad} = \frac{1}{2} R_r |I_0|^2 = 40\pi^2 |I_0|^2 \left( \frac{dl}{\lambda_0} \rightx)^2 and S<sub>i</mathsub>(x) are the cosine and sine integrals, respectively:
=== Defining a Field Sensor ===
[[File:PROP18<math> C_i(2x).png|thumb|350px|EM.Terrano's Field Sensor dialog]]As an asymptotic electromagnetic field solver, the SBR simulation engine can compute the electric and magnetic field distributions in a specified plane. In order to view these field distributions, you must first define field sensor observables before running the SBR simulation. To do that, right click on the '''Field Sensors''' item in the '''Observables''' section of the Navigation Tree and select '''Insert New Observable...'''. The Field Sensor Dialog opens up. At the top of the dialog and in the section titled '''Sensor Plane Location''', first you need to set the plane of field calculation. In the dropdown box labeled '''Direction''', you have three options X, Y, and Z, representing the"normals" to the XY, YZ and ZX planes, respectively. The default direction is Z, i.e. XY plane parallel to the substrate layers. In the three boxes labeled '''Coordinates''', you set the coordinates of the center of the plane. Then, you specify the '''Size''' of the plane in project units, and finally set the '''Number of Samples''' along the two sides of the sensor plane. The larger the number of samples, the smoother the near field map will appear. = - \int_{x}^{\infty} \frac{ \text{cos} \tau}{\tau} d\tau </math>
In the section titled Output Settings, you can also select the field map type from two options: '''Confetti''' and '''Cone'''. The former produces an intensity plot for field amplitude and phase, while the latter generates a 3D vector plot. In the confetti case, you have an option to check the box labeled '''Data Interpolation''', which creates a smooth and blended <math> S_i(digitally filteredx) map. In the cone case, you can set the size of the vector cones that represent the field direction. At the end of a sweep simulation, multiple field map are produced and added to the Navigation Tree. You can animate these maps. However, during the sweep only one field type is stored, either the E-field or H-field. You can choose the field type for multiple plots using the radio buttons in the section titled '''Field Display - Multiple Plots'''. The default choice is the E-field. = \int_{0}^{x} \frac{ \text{sin} \tau}{\tau} d\tau </math>
Once you close the Field Sensor dialog, its name is added under the '''Field Sensors''' node of the Navigation Tree. At the end of a SBR simulation, the field sensor nodes in the Navigation Tree become populated by the magnitude and phase plots of the three vectorial components of the electric ('''E''') and magnetic ('''H''') field as well as the total electric and magnetic fields.
[[Image:MOREIn the case of a half-wave dipole, L = λ<sub>0</sub>/2, and D<sub>0</sub> = 1.png|40px]] Click here 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 learn more about '''[[Data_Visualization_and_Processing#Visualizing_3D_Near-Field_Maps | Visualizing 3D Near Field Maps]]'''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:PROP18MDipole radiators.png|thumb|450px720px|Computed total electric field distribution of a vertical short dipole radiator 2m above the default global ground at 1GHzEM.]] </td><td> [[Image:PROP18N.png|thumb|450px|Computed total magnetic field distribution of a vertical short Terrano's native half-wave dipole radiator 2m above the default global ground at 1GHztransmitter and receiver.]] </td>
</tr>
</table>
=== Computing Radiation Patterns In SBR ===On the other hand, we you specify a user-defined antenna pattern for the transmitter or receiver sets, you import a 3D radiation pattern file that contains all the values of E<sub>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:
[[File:PROP18(3)* DPL_STD_X.png|thumb|350px|EM.Terrano's Radiation Pattern dialog.]]RAD[[EM* DPL_STD_Y.Terrano]] lets you compute the effective far-field radiation pattern of your radiating structure in the presence of surrounding scatterers and obstructing objects. Computing the radiation pattern of an antenna or any radiating structure in [[EM.Cube]]'s full-wave computational modules like [[EM.Tempo]], [[EM.Picasso]] or [[EM.Libera]] is fairly straightforward. Using [[EM.Illumina]] you can use an asymptotic physical optics solver to model the effects of the mounting platform on the performance of an installed antenna. Computing radiation patterns in [[EM.Terrano]] may not seem intuitive at first because you have to import the radiation patterns from external data files after all. RAD In order to visualize a radiation pattern in [[EM.Terrano]], you have to define a "Far Fields" observable. To do so, right-click on the '''Far Fields''' item in the '''Observables''' section of the navigation tree and select '''Insert New Radiation Pattern...''' from the contextual menu. This opens up the Radiation Pattern dialog. You can accept most of the default settings. The most important [[parameters]] to change are the angular resolutions. These are called '''Theta Angle Increment''' and '''Phi Angle Increment''', both of which have default values of 5°. When you define a far-field observable in [[EM.Terrano]], a collection of <u>invisible</u>, isotropic receivers are placed on the surface of a large sphere that encircles your propagation scene and all of its objects. These receivers are equally spaced 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 3D 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* DPL_STD_Z. RAD
{{and they are located in the folder "\Documents\EMAG\Models" on your computer. Note| Computing radiation patterns using [[EMthat these are full-wave simulation data and do not involve any approximate assumptions.Terrano]]'s SBR solver typically takes much longer computation times than using [[EM.Cube]]'s other computational modules.}} [[Image:MORE.png|40px]] Click here To use these files as an alternative to the native dipole radiators, you need to learn more about select the '''[[Data_Visualization_and_Processing#Visualizing_3D_Radiation_Patterns | Visualizing 3D Radiation Patterns]]User Defined Antenna Pattern'''radio button as the the radiator type in the transmitter or receiver set property dialog.
[[Image:MORE=== A Note on the Rotation of Antenna Radiation Patterns ===Â EM.png|40px]] Click here Terrano's Transmitter Set dialog and Receiver Set dialog both allow you to learn more about rotate an imported radiation pattern. In that case, you need to specify the '''[[Data_Visualization_and_Processing#2D_Radiation_and_RCS_Graphs | Plotting 2D Radiation Graphs]]Rotation'''angles in degrees about the X-, Y- and Z-axes. It is important to note that these rotations are performed sequentially and in the following order: first a rotation about the X-axis, then a rotation about the Y-axis, and finally a rotation about the Z-axis. In addition, all the rotations are performed with respect to the "rotated" local coordinate systems (LCS). 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 performed with respect to the new Y<sup>′</sup>-axis and transforms the X<sup>′</sup>Y<sup>′</sup>Z<sup>′</sup> LCS to a 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.
<table>
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<td> [[ImageFile:PROP18PPROP22B.png|thumb|450px300px|Computed 3D radiation pattern The local coordinate system of two vertical short a linear dipole radiators placed 1m apart in antenna.]] </td><td> [[File:PROP22C.png|thumb|600px|Rotating the dipole antenna by +90° about the local Y-axis.]] </td></tr></table><table><tr><td> [[File:PROP22D.png|thumb|720px|Rotating the dipole antenna by +90° about the local X-axis and then by -45° by the free space at 1GHzlocal Y-axis.]] </td>
</tr>
</table>
== Discretizing the Propagation Scene = Adjustment of Tx/Rx Elevation above a Terrain Surface ===
=== Why Do You Need When your transmitters or receivers are located above a flat terrain like the global ground, their Z-coordinates are equal to Discretize 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 you the option to adjust the transmitter and receiver sets to the terrain elevation. This is done for individual transmitter sets and individual receiver sets. At the top of the Transmitter Dialog there is a check box labeled "'''Adjust Tx Sets to Terrain Elevation'''". Similarly, at the top of the Receiver Dialog there is a check box labeled "'''Adjust Rx Sets to Terrain Elevation'''". These boxes are unchecked by default. As a result, your transmitter sets or receiver sets coincide with their associated base points in the project workspace. If you check these boxes and place a transmitter set or a receiver set above an irregular terrain, the transmitters or receivers are elevated from the location of their associated base points by the amount of terrain elevation as can be seen in the Scene? ===figure below.
EM.Terrano's SBR ray tracer uses a method known as Geometrical Optics (GO) To better understand why there are two separate sets of points 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 on their way and get reflectedscene, diffracted or transmitted. EM.Terrano's SBR solver can only handle diffraction off linear edges and reflection from and transmission through planar material interfaces. The underlying theory for calculation of reflection, transmission and diffraction coefficients indeed assumes material media of infinite extents. When note that a ray hits a specular point on the surface of the obstructing array (CAD object, a local planar surface assumption ) is made at the specular point.  [[Image:Info_icon.png|40px]] Click here used to learn more about the theory of '''[[SBR Method]]'''create a uniformly spaced base set. If your propagation scene contains only cubic buildings on the flat global ground, the assumptions of linear edges and planar facets hold well although they violate the infinite extents assumption. In many practical scenarios, however, your buildings may have curved surface or the terrain may be irregular. EM.Terrano allows The array object always preserves its grid topology as you to draw any type of surface or solid CAD objects under impenetrable and penetrable surface groups or penetrable volumes. Some of these objects contain curved surfaces or curved boundaries and edges such as cylinders, cones, etc. In order to address all such cases in move it around the most general context, EM.Terrano always uses a triangular surface mesh of all the objects in your propagation scene. Even rectangular facets of cubic buildings are meshed using triangular cells. This is done to be able to properly discretize composite buildings made of conjoined cubic objects.  Unlike [[EM.Cube]]'s other computational modulesHowever, the density transmitters or resolution of EM.Terrano's surface mesh does not depend on receivers associated with this point array object are elevated above the operating frequency and is not expressed in terms of the wavelength. Its sole purpose is to discretize curved and irregular scatterers into flat facets terrain and linear edgesno longer follow a strictly uniform grid. Therefore, geometrical fidelity is If you move the only criterion for the quality of an SBR mesh. It is important base set from its original position to note that discretizing smooth objects using a triangular surface mesh typically creates a large number of small edges among new location, the facets that are simply mesh artifacts and should not be considered as diffracting edges. For examplebase points' topology will stay intact, each rectangular face of a cubic building is subdivided into four triangles along while the two diagonals. The four internal edges lying inside the face are obviously not diffracting edges. A lot of subtleties like these must associated transmitters or receivers will be taken into account by redistributed above the SBR solver to run accurate and computationally efficient simulationsterrain based on their new elevations.
<table>
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<td> [[Image:PROP20BPROP MAN8.png|thumb|400pxleft|Three building objects with different basic 640px|A transmitter (red) and composite shapesa 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 three building objectsadjusted transmitters and receivers on the terrain are also visible in the figure.]] </td>
</tr>
</table>
=== 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.
<table>
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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 three building objects with an edge length of 10m and a curvature angle tolerance of 10°.]] </td>
</tr>
</table>
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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]]'''.
<table>
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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>
</tr>
</table>
== Running an SBR Simulation Ray Tracing Simulations in EM.Terrano ==
=== SBR Simulation Types ===EM.Terrano provides a number of different simulation or solver types:
[[Image:PROP12.png|thumb|400px|EM.Terrano's Simulation Run dialog.]]* 3D Field SolverEM.Terrano offers three types of ray tracing simulations:* SBR Channel Analyzer* Log-Haul Channel Analyzer* Communication Link Solver* Radar Link Solver
* Single-Frequency Analysis* Frequency Sweep* Parametric SweepThe first three simulation types are described below. For a description of EM.Terrano's Radar Simulator, follow this link.
A single=== Running a Single-frequency Frequency SBR analysis is the simplest type of ray tracing simulation and involves the following steps:Analysis ===
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 in EM.Terrano. It involves the following steps:Â * 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:Info_icon.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:Info_iconUrbanCanyon10.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:Info_iconUrbanCanyon15.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.
<table>
<tr>
<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>
</tr>
</table>
=== 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.
<table>
<tr>
<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>
</tr>
</table>
=== 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.
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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 receiver.]] </td><td> [[Image:prop_run6_tn.png|thumb|550px|Analyzing a selected ray from in the ray data dialograndom city scene.]] </td>
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=== The Standard Output Data Files File ===
[[Image:prop_run8_tn.png|thumb|800px|A typical SBR 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:
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.
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[[Image:prop_run8_tn.png|thumb|left|720px|A typical SBR output data file.]]
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=== Plotting Other Simulation Results ===
Besides "sbr_results.out", [[EM.Terrano ]] writes a number of other ASCII data files to your project folder. You can view or plot these data in [[EM.Cube]]'s Data Manager. You can open data manager by clicking the '''Data Manager''' [[File:data_manager_icon.png]] button of the '''Simulate Toolbar''' or by selecting '''Menu > Simulate > Data Manager''' from the menu bar or by right-clicking on the '''Data Manager''' item of the navigation tree and selecting '''Open Data Manager...''' from the contextual menu or by using the keyboard shortcut {{key|Ctrl+D}}.
The available data files in the "2D Data Files" tab of Data Manger include:
* '''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.
When you run a frequency or parametric sweep in [[EM.Terrano]], a tremendous amount of data may be generated. [[EM.Terrano ]] only stores the '''Received Power''', '''Path Loss''' and '''SNR''' of the selected receiver
in ASCII data files called "PREC_i.DAT", "PL_i.DAT" and "SNR_i.DAT", where is the index of the receiver set in your scene. These quantities are tabulated vs. the sweep variable's samples. You can plot these files in EM.Grid.
[[Image:Info_icon.png|40px]] Click here to learn more about working with data filed and plotting graphs in [[EM.Cube]]'s '''[[Data_Visualization_and_ProcessingDefining_Project_Observables_%26_Visualizing_Output_Data#Working_with_Data_FilesThe_Data_Manager | Data Manager]]'''.
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<td> [[Image:PROP20ETerrano pathloss.png|thumb|350px360px|Cartesian graph of path loss.]] </td><td> [[Image:PROP20FTerrano delay.png|thumb|350px360px|Bar graph of power delay profile.]] </td>
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<td> [[Image:PROP20GTerrano ARR phi.png|thumb|350px360px|Polar stem graph of Phi angle of arrival.]] </td><td> [[Image:PROP20HTerrano ARR theta.png|thumb|350px360px|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>Â === Visualizing 3D Radiation Patterns of Transmit and Receive Antennas in the Scene ===Â When you designate a "User Defined Antenna Pattern" as the radiator type of a transmitter set or a receiver set, EM.Terrano copies the imported radiation pattern data file from its original folder to the current project folder. The name of the ".RAD" file is listed under the '''3D Data Files''' tab of the data manager. Sometimes it might be desired to visualize these radiation patterns in your propagation scene at the 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. Â <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>Â By Default, [[EM.Cube]] always visualizes the 3D radiation patterns at the origin of coordinates, i.e. at (0, 0, 0). This is because that radiation pattern data are computed in the standard spherical coordinate system centered at (0, 0, 0). The theta and phi components of the far-zone electric fields are defined with respect to the X, Y and Z axes of this system. When visualizing the 3D radiation pattern data in a propagation scene, it is more intuitive to display the pattern at the location of the transmitter or receiver. The Radiation Pattern dialog allows you to translate the pattern visualization to any arbitrary point in the project workspace. It also allows you to scale up or scale down the pattern visualization with respect to the background scene. Â In the example shown above, the imported pattern data file is called "Dipole_Array1.RAD". Therefore, the label of the radiation pattern observable is chosen to be "Dipole_Array1". The theta and phi angle increments are both 1° in this case. The radiation pattern has been elevated by 10m to be positioned at the location of the transmitter and a scaling factor of 0.3 has been used. Â <table><tr><td>[[Image:UrbanCanyon8.png|thumb|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>Â There 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: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 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>
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=== 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:UrbanCanyon5.png|thumb|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|48px30px]] '''[[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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