[[Image:Splash-prop.jpg|right|800px720px]]<strong><font color="#4e1985" size="4">A True 3D, Coherent, Polarimetric Ray Tracer That Simulates Very Large Urban Scenes In Just Few Minutes!</font></strong>
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<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=EM.Tempo]] [[image:postatic-ico.png | link=EM.IlluminaFerma]] [[image:staticplanar-ico.png | link=EM.FermaPicasso]] [[image:planarmetal-ico.png | link=EM.PicassoLibera]] [[image:metalpo-ico.png | link=EM.LiberaIllumina]] </td>
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[[Image:Tutorial_icon.png|40px30px]] '''[[EM.Cube#EM.Terrano_Tutorial_Lessons Terrano_Documentation | EM.Terrano Tutorial Gateway]]'''
[[Image:Back_icon.png|40px30px]] '''[[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.
Since its introduction in 2002, EM.Terrano has helped wireless engineers around the globe model the physical channel and the mechanisms by which radio signals propagate from transmitters to receiversin various environments. EM.Terranoâs advanced ray tracing simulator finds the dominant propagation paths at each specific physical site. It calculates the true signal characteristics at the actual locations using physical databases of the buildings and terrain at a given site, not those of a statistically average or representative environment. The earlier versions of EM.Terrano's SBR solver relied on certain assumptions and approximations such as the vertical plane launch (VPL) method or 2.5D analysis of urban canyons with prismatic buildings using two separate vertical and horizontal polarizations. In 2014, we introduced a new fully 3D polarimetric SBR solver that accurately traces all the three X, Y and Z components of the electric fields (both amplitude and phase) at every point inside the computational domain. Using a full 3D CAD modeler, you can now set up any number of buildings with arbitrary geometries, no longer limited to vertical prismatic shapes. Versatile interior wall arrangements allow indoor propagation modeling inside complex building configurations. The most significant recent improvement development is an entirely new a multicore parallelized SBR simulation engine that takes advantage of ultrafast k-d tree algorithms borrowed from the field of computer graphics and video gamingto achieve the ultimate speed and efficiency in geometrical optics ray tracing.
[[Image:Tutorial_iconInfo_icon.png|40px30px]] Click here to access learn more about the '''[[EM.Cube#EM.Terrano_Tutorial_Lessons Basic Principles of SBR Ray Tracing | EM.Terrano Tutorial GatewayBasic SBR Theory]]'''.
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[[Image:PROP250AManhattan1.png|thumb|left|640px420px|A large urban propagation scene featuring lower Manhattan.]]
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=== EM.Terrano as the Propagation Module of EM.Cube ===
EM.Terrano is the ray tracing '''Propagation Module''' of '''[[EM.Cube]]''', a comprehensive, integrated, modular electromagnetic modeling environment. EM.Teranno Terrano shares the visual interface, 3D parametric CAD modeler, data visualization tools, and many more utilities and features collectively known as [[Building_Geometrical_Constructions_in_CubeCAD | CubeCAD ]] with all of [[EM.Cube]]'s other computational modules.
With the seamless integration of EM.Terrano with [[EM.Cube]]'s other modules, you can now model complex antenna systems in [[EM.Tempo]], [[EM.Libera]], [[EM.Picasso]] or [[EM.Illumina]], and generate antenna radiation patterns that can be used to model directional transmitters and receivers at the two ends of your propagation channel. Conversely, you can analyze a propagation scene in EM.Terrano, collect all the rays received at a certain receiver location and import them as coherent plane wave sources to [[EM.Tempo]], [[EM.Libera]], [[EM.Picasso]] or [[EM.Illumina]].
[[Image:Info_icon.png|40px30px]] Click here to learn more about '''[[Getting_Started_with_EM.CUBE Cube | EM.Cube Modeling Environment]]'''.
[[Image:Info_icon=== Advantages & Limitations of EM.png|40px]] Click here Terrano's SBR Solver === EM.Terrano's SBR simulation engine utilizes an intelligent ray tracing algorithm that is based on the concept of k-dimensional trees. A k-d tree is a space-partitioning data structure for organizing points in a k-dimensional space. k-d trees are particularly useful for searches that involve multidimensional search keys such as range searches and nearest neighbor searches. In a typical large radio propagation scene, there might be a large number of rays emanating from the transmitter that may never hit any obstacles. For example, upward-looking rays in an urban propagation scene quickly exit the computational domain. Rays that hit obstacles on their path, on the other hand, generate new reflected and transmitted rays. The k-d tree algorithm traces all these rays systematically in a very fast and efficient manner. Another major advantage of k-d trees is the fast processing of multi-transmitters scenes.  EM.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 three vectorial field components are computed, analyzed and preserved throughout the entire ray tracing process from the source location to learn more about the basic functionality field observation points. You can visualize the magnitude and phase of all six electric and magnetic field components at any point in the computational domain. In most scenes, the buildings and the ground or terrain can be assumed 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 simple reflection or transmission coefficient formulas for homogeneous medium interfaces. EM.Terrano calculates the reflection and transmission coefficients of multilayer structures as functions of incident angle, frequency and polarization and uses them at the respective specular points.  It is very important to keep in mind that SBR is an asymptotic electromagnetic analysis technique that is based on Geometrical Optics (GO) and the Uniform Theory of Diffraction (UTD). It is not a "full-wave" technique, and it does not provide a direct numerical solution of Maxwell'''s equations. SBR makes a number of assumptions, chief among them, a very high operational frequency such that the length scales involved are much larger than the operating wavelength. Under this assumed regime, electromagnetic waves start to behave like optical rays. Virtually all the calculations in SBR are based on far field approximations. In order to maintain a high computational speed for urban propagation problems, EM.Terrano ignores double diffractions. Diffractions from edges give rise to a large number of new secondary rays. The power of diffracted rays drops much faster than reflected rays. In other words, an edge-diffracted ray does not diffract again from another edge in EM.Terrano. However, reflected and penetrated rays do get diffracted from edges just as rays emanated directly from the sources do. <table><tr><td> [[Building_Geometrical_Constructions_in_CubeCAD Image:Multipath_Rays.png| CubeCADthumb|left|500px|A multipath urban propagation scene showing all the rays collected by a receiver.]]'''.</td></tr></table>
== EM.Tempo Terrano Features at a Glance ==
[[Image:KDFig10.png|thumb|500px|A large urban propagation scene with a global lossy flat ground.]]
[[Image:KDFig11.png|thumb|500px|Computed received power coverage map of the above urban propagation scene.]]
=== Scene Definition / Construction ===
<ul>
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Buildings/blocks with arbitrary geometries and material properties including multilayer walls and user defined macromodels</li>
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Buildings/blocks with impenetrable surfaces or penetrable surfacesusing thin wall approximation</li>
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Terrain with arbitrary material properties including lossy multilayer ground, user defined macromodels or an empirical soil modelMultilayer walls for indoor propagation scenes</li>
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Native terrain generator Penetrable volume blocks with terrain catalog arbitrary geometries and user defined equation-based surface profiles including random rough surface terrainmaterial properties</li>
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Import of shape shapefiles and STEP, IGES and STL CAD model files for scene construction</li>
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Import of digital elevation map (DEM) terrainTerrain surfaces with arbitrary geometries and material properties and random rough surface profiles</li>
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Penetrable volume blocks with arbitrary material properties or based on fog, rain or Weissberger vegetation Import of digital elevation map (DEM) terrain models</li>
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Easy construction Python-based random city wizard with randomized building locations, extents and orientations</li> <li> Python-based wizards for generation of indoor scenes using arbitrary penetrable surfaces parameterized multi-story office buildings and several terrain scene types</li> <li> Standard half-wave dipole transmitters and receivers oriented along the principal axes</li> <li> Short Hertzian dipole sources with thin wall definitionsarbitrary orientation</li> <li> Isotropic receivers or receiver grids for wireless coverage modeling</li>
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Radiator sets with 3D directional antenna patterns (imported from other modules or external files)</li>
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Interchangeable radiator-based definition of transmitters and receivers (networks of transceivers)</li>
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Multiple transmitters and transmitter arrays with coherent ray superposition</li>
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Multiple receivers and receiver grids for coverage modeling</li>
</ul>
GTD/UTD diffraction models for diffraction from building edges and terrain</li>
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Triangular surface mesher mesh generator for discretization of arbitrary block geometries</li>
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Super-fast geometrical/optical ray tracing using advanced k-d tree algorithms</li>
Intelligent ray tracing with user defined angular extents and resolution</li>
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Ray reflection, edge diffraction and ray transmission through multilayer thin walls and material volumes</li>
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Communication link analysis for superheterodyne transmitters and receivers</li>
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User defined macromodels 17 digital modulation waveforms for reflection and transmission coefficients the calculation of blocks E<sub>b</sub>/N<sub>0</sub> and terrain Bit error rate (imported from other modules or external filesBER)</li>
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Real-time superposition Incredibly fast frequency sweeps of synchronized transmittersthe entire propagation scene in a single SBR simulation run</li>
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Incredibly fast frequency Parametric sweeps of the entire propagation sceneelements like building properties, or radiator heights and rotation angles</li>
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Parametric sweeps Statistical analysis of the propagation scene elements like building properties, radiator heights and rotation angles, or superheterodyne transmitter and receiver parameters</li>
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Statistical analsyis of the propagation scenePolarimetric channel characterization for MIMO analysis</li>
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Remote simulation capability"Almost real-time" Polarimatrix solver using an existing ray database</li>
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Both Windows and Linux versions of SBR simulation engine available"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>
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Standard output parameters for received power, path loss, SNR, E<sub>b</sub>/N<sub>0</sub> and BER at each individual receiver</li>
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Graphical visualization of propagating rays in the scene</li>
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Received power coverage maps</li>
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Link connectivity maps (based on minimum required SNR and BER)</li>
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Color-coded intensity plots of polarimetric electric field distributions</li>
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Link connectivity maps (based on minimum required SNR)</li> <li> Incoming ray data analysis at each receiverincluding delay, angles of arrival and departure</li>
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Cartesian plots of path loss along defined paths</li>
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Power delay profileof the selected receiver</li> <li> Polar stem charts of angles of arrival and departure of the selected receiver</li>
</ul>
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== A Ray Tracing Simulation Primer ==
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=== Physics-Based Propagation Channel Modeling Using SBR Ray Tracing ===
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Every wireless communication system involves a transmitter that transmits some sort of signal (voice, video, data, etc.), a receiver that receives and detects the transmitted signal, and a channel in which the signal is transmitted into the air and travels from the location of the transmitter to the location of the receiver. The channel is the physical medium in which the electromagnetic waves propagate. The successful design of a communication system depends on an accurate link budget analysis that determines whether the receiver receives adequate signal power to detect it against the background noise. The simplest channel is the free space. In a free-space line-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 applications.
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[[Image:Info_icon.png|40px]] Click here to learn more about the theory of a '''[[A Review of Maxwell's Equations#Free-Space Wave Propagation | Free-Space Propagation Channel]]'''.
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Real communication channels, however, are more complicated and involve a large number of wave scatterers. For example, in an urban environment, the obstructing buildings, vehicles and vegetation reflect, diffract or attenuate the propagating radio waves. As a result, the receiver receives a distorted signal that contains several components with different power levels and different time delays arriving from different angles. The different rays arriving at a receiver location create constructive and destructive interference patterns. This is known as the multipath effect. This together with the shadowing effects caused by building obstructions lead to channel fading. The use of statistical models for prediction of fading effects is widely popular among communication system designers. These models are either based on measurement data or derived from simplistic analytical frameworks. The statistical models often exhibit considerable errors especially in areas having mixed building sizes. In such cases, one needs to perform a physics-based, site-specific analysis of the propagation environment to accurately identify and establish all the possible signal paths from the transmitter to the receiver. This involves an electromagnetic analysis of the scene with all of its geometrical and physical details.
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[[Image:multi1_tn.png|thumb|left|550px|A multipath propagation scene showing all the rays arriving at a particular receiver.]]
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Link budget analysis for a multipath channel is a challenging task due to the large size of the computational domains involved. Typical propagation scenes usually involve length scales on the order of thousands of wavelengths. To calculate the path loss between the transmitter and receiver, one must solve Maxwell's equations in an extremely large space. Full-wave numerical techniques like the Finite Difference Time Domain (FDTD) method, which require a fine discretization of the computational domain, are therefore impractical for solving large-scale propagation problems. The practical solution is to use asymptotic techniques such as SBR, which utilize analytical techniques over large distances rather than a brute force discretization of the entire computational domain. Such asymptotic techniques, of course, have to compromise modeling accuracy for computational efficiency.
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EM.Terrano provides an asymptotic ray tracing simulation engine that is based on a technique known as Shooting-and-Bouncing-Rays (SBR). In this technique, propagating spherical waves are modeled as ray tubes or beams that emanate from a source, travel in space, bounce from obstacles and are collected by the receiver. As rays propagate away from their source (transmitter), they begin 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.
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When a ray hits an obstructing surface, one or more of the following phenomena may happen:
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# Reflection from the locally flat surface
# Transmission through the locally flat surface
# Diffraction from an edge between two conjoined locally flat surfaces
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[[Image:Info_icon.png|40px]] Click here to learn more about the '''[[SBR Method | Theory of SBR Method]]'''.
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=== Advantages & Limitations of EM.Terrano's SBR Solver ===
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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.
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EM.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 three vectorial field components are computed, analyzed and preserved throughout the entire ray tracing process from the source location to the field observation points. You can visualize the magnitude and phase of all six electric and magnetic field components at any point in the computational domain. In most scenes, the buildings and the ground or terrain can be assumed 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 simple reflection or transmission coefficient formulas for homogeneous medium interfaces. EM.Terrano calculates the reflection and transmission coefficients of multilayer structures as functions of incident angle, frequency and polarization and uses them at the respective specular points.
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It is very important to keep in mind that SBR is an asymptotic electromagnetic analysis technique that is based on Geometrical Optics (GO) and the Uniform Theory of Diffraction (UTD). It is not a "full-wave" technique, and it does not provide a direct numerical solution of Maxwell's equations. SBR makes a number of assumptions, chief among them, a very high operational frequency such that the length scales involved are much larger than the operating wavelength. Under this assumed regime, electromagnetic waves start to behave like optical rays. Virtually all the calculations in SBR are based on far field approximations. In order to maintain a high computational speed for urban propagation problems, EM.Terrano ignores double diffractions. Diffractions from edges give rise to a large number of new secondary rays. The power of diffracted rays drops much faster than reflected rays. In other words, an edge-diffracted ray does not diffract again from another edge in EM.Terrano. However, reflected and penetrated rays do get diffracted from edges just as rays emanated directly from the sources do.
== Building a Propagation Scene in EM.Terrano ==
=== The Various Elements of a Propagation Scene ===
A typical propagation scene in EM.Terrano consists of several elements. At a 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.TErranoTerrano, 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.
A more complicated propagation scene usually contains several buildings, walls, or other kinds of scatterers and wave obstructing objects. You models 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 common type of interaction with incident rays. EM.Terrano offer the following types of object blocks:
{| 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.Cube's Materials , Sources, Devices & Other Physical Object Types#Impenetrable Surface | Impenetrable Surface]]'''| style="width:250px200px;" | 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 EM.Cube's Materials , Sources, Devices & Other Physical Object Types#Penetrable Surface | Penetrable Surface]]'''| style="width:250px200px;" | Ray reflection, ray diffraction, ray transmission through thin wallsin free space
| style="width:250px;" | All solid & surface geometric objects, no curve objects
| style="width:300px;" | Behaves similar to impenetrable surface and uses thin wall approximation for generating transmitted rays, used to model hollow buildings with ray penetration, entry and exit
|-
| style="width:30px;" | [[File:terrain_group_icon.png]]| style="width:150px;" | '''[[Glossary of EM.Cube's Materials , Sources, Devices & Other Physical Object Types#Terrain Surface | Terrain Surface]]'''| style="width:250px200px;" | 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 elevation of all the buildings and transmitters and receivers located above it
|-
| style="width:30px;" | [[File:penet_vol_group_icon.png]]| style="width:150px;" | '''[[Glossary of EM.Cube's Materials , Sources, Devices & Other Physical Object Types#Penetrable Volume | Penetrable Volume]]'''| style="width:250px200px;" | Ray reflection, ray diffraction, ray transmission in and ray attenuation inside homogeneous material media
| style="width:250px;" | All solid geometric objects, no surface or curve objects
| style="width:300px;" | Used to model wave propagation inside a volumetric material block, also used for creating individual solid walls and interior building partitions and panels in indoor scenes
|-
| style="width:30px;" | [[File:base_group_icon.png]]| style="width:150px;" | '''[[Glossary of EM.Cube's Materials , Sources, Devices & Other Physical Object Types#Base Location Set | Base Location Set]]'''| style="width:250px200px;" | Either ray generation or ray reception
| style="width:250px;" | Only point objects
| style="width:300px;" | Required for the definition of transmitters and receivers
|-
| style="width:30px;" | [[File:scatterer_group_icon.png]]
| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Point Scatterer Set | Point Scatterer Set]]
| style="width:200px;" | Ray reception and ray scattering
| style="width:250px;" | Only point, box and sphere objects
| style="width:300px;" | Required for the definition of point scatterers as targets in a radar simulation
|-
| style="width:30px;" | [[File:Virt_group_icon.png]]
| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Virtual_Object_Group | Virtual Object]]
| style="width:200px;" | No ray interaction
| style="width:250px;" | All types of objects
| style="width:300px;" | Used for representing non-physical items
|}
Click on each type to learn more about it in the [[Glossary of EM.Cube's Materials , Sources, Devices & Other Physical Object Types]].
Impenetrable surfaces, penetrable surfaces, terrain surfaces and penetrable volumes represent all the objects that obstruct the propagation of electromagnetic waves (rays) in the free space. What differentiates them is the types of physical phenomena that are used to model their interaction with the impinging rays. EM.Terrano discretizes geometric objects into a number of flat facets. The field intensity, phase and power of the reflected and transmitted rays depend on the material properties of the obstructing facet. The specular surface of a facet can be modeled locally as a simple homogeneous dielectric half-space or as a multilayer medium. In that respect, all the obstructing objects such as buildings, walls, terrain, etc. behave in a similar way:
* They terminate an impinging ray and replace it with one or more new rays.
An outdoor propagation scene typically involves several buildings modeled by impenetrable surfaces. Rays hit the facets of impenetrable buildings and bounce back, but they do not penetrate the object. It is assumed that the interior of such buildings are highly dissipative due to wave absorption or diffusion. An indoor propagation scene typically involves several walls, a ceiling and a floor arranged according to a certain building layout. Penetrable surfaces are used to model the exterior and interior walls of buildings. Rays reflect off these surfaces and diffract off their edges. They also penetrate the thin surface and continue their path in the free space on the other side of the wall. Terrain surfaces with irregular shapes or possibly random rough surfaces are used as an alternative to the flat global ground. You can also build mixed scenes involving both impenetrable and penetrable blocks or irregular terrain. In the context of a propagation scene, penetrable volumes are often used to model block of rain, fog or vegetation. Base location sets are used to geometrically represent point transmitters and point receivers in the project workspace.
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Sometimes it is helpful to draw graphical objects as visual clues in the project workspace. These non-physical objects must belong to a virtual object group. Virtual objects are not discretized by EM.Terrano's mesh generator, and they are not passed onto the input data files of the SBR simulation engine.
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[[Image:PROP MAN2.png|thumb|left|720px|An urban propagation scene generated by EM.Terrano's "Random City" and "Basic Link" wizards. It consists of 25 cubic brick buildings, one transmitter and a large two-dimensional array of receivers. ]]
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=== Organizing the Propagation Scene by Block Groups ===
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[[Image:PROP MAN1.png|thumb|left|480px|EM.Terrano's navigation tree.]]
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{{Note|You can only import external CAD models (STEP, IGES, STL, DEM, etc.) only to the CubeCAD module. You can then transfer the imported objects from CubeCAD to EM.Terrano.}}
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[[Image:Info_icon.png|40px]] Click here for a general discussion of '''[[Defining Materials in EM.Cube]]'''.
=== Moving Objects Among Different Block Groups ===
=== Adjustment of Block Elevation on Underlying Terrain Surfaces ===
In [[EM.Terrano]], buildings and all other geometric objects are initially drawn on the XY plane. In other words, the Z-coordinates of the local coordinate system (LCS) of all blocks are set to zero until you change them. Since the global ground is located a z = 0, your buildings are seated on the ground. When your propagation scene has an irregular terrain, you would want to place your buildings on the surface of the terrain and not buried under it. This can be done automatically as part of the definition of the block group. Open the property dialog of a block group and check the box labeled '''Adjust Block to Terrain Elevation'''. All the objects belonging to that block are automatically elevated in the Z direction such that their bases sit on the surface of their underlying terrain. In effect, the LCS of each of these individual objects is translated along the global Z-axis by the amount of the Z-elevation of the terrain object at the location of the LCS.
{{Note| You have to make sure that the resolution of your terrain, its variation scale and building dimensions are all comparable. Otherwise, on a rapidly varying high-resolution terrain, you will have buildings whose bottoms touch the terrain only at a few points and parts of them hang in the air.}}
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[[Image:PROP MAN6.png|thumb|left|480px360px|A set of buildings on an undulating terrain without elevation adjustment.]]
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[[Image:PROP MAN7.png|thumb|left|480px360px|The set of buildings on the undulating terrain after elevation adjustment.]]
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== EM.Terrano's Ray Domain & Global Ground Environment ==
=== Why Do You Need a Finite Computational Domain? ===
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[[Image:PROP4Global environ.png|thumb|left|480px720px|EM.Terrano's global ground settings Global Environment Settings dialog.]]
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== Defining Point Transmitters & Point Receivers for Your Propagation Scene ==
=== Defining a Transmitter Set The Nature of Transmitters & Receivers ===
Transmitters act as sources in a In EM.Terrano, transmitters and receivers are indeed point radiators used for transmitting and receiving signals at different locations of the propagation scene. A transmitter is From a geometric point of view, both transmitters and receivers are represented by point objects or point arrays. These are grouped as base locations in the "Physical Structure" section of the navigation tree. As radiators, transmitters and receivers are defined by a radiator type with a fully polarimetric certain far-field radiation pattern defined over the entire 3D space in the standard spherical coordinate system. You can model a radiating structure using Consistent with [[EM.Cube]]'s other computational modules, [[EM.Tempo]]transmitters are categorizes as an excitation source, [[EMwhile receivers are categorized as a project observable.Picasso]]In other words, [[EM.Libera]] or [[EM.Illumina]], and a transmitter is used to generate a 3D radiation pattern data file for it. The far-field radiation patter data are stored electromagnetic waves that propagate in a specially formatted file with a "'''the physical scene.RAD'''" file extension. It file contains columns of spherical φ and θ angles as well as A receiver, on the real other hand, is used to compute the received fields and imaginary parts of the complexreceived signal power or signal-valued farto-zoned electric field components '''E<sub>θ</sub>''' and '''E<sub>φ</sub>'''noise ratio (SNR). The θ- For this reason, transmitters are defined and φ-components listed under the "Sources" sections of the far-zone electric field determine navigation tree, while receivers are defined and listed under the polarization of the transmitting radiator"Observables" section.
[[ImageEM.Terrano provides three radiator types for point transmitter sets:Info_icon.png|40px]] Click here to learn more about the format of '''[[Data_Visualization_and_Processing#Far_Field_Data_Files | Radiation Pattern Files]]'''.
A transmitter set always needs to be associated with an existing base location set in #Half-wave dipole oriented along one of the project workspace. Thereforethree principal axes#Two collocated, you cannot define a transmitter for your scene before drawing a point object under a base location set. orthogonally polarized, isotropic radiators #User defined (arbitrary) antenna with imported far-field radiation pattern
[[Image:Info_icon.png|40px]] Click here to learn how to define a '''[[Glossary of EM.Cube's Excitation Sources# | Transmitter Set]]'''.Terrano also provides three radiator types for point receiver sets:
#Half-wave dipole oriented along one of the three principal axes
#Polarization-matched isotropic radiator
#User defined (arbitrary) antenna with imported far-field radiation pattern
To The default transmitter and receiver radiator types are both vertical (Z-directed) half-wave dipoles.  There are three different ways to define a transmitter source set or a receiver set: *By defining 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 === Defining a Point Transmitter Set in the Formal Way === Transmitters act as sources in a propagation scene. 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.Terranogives you three options for the radiator associated with a point transmitter: * Half-wave dipole* Orthogonally polarized isotropic radiators* User defined antenna pattern  By default, EM.Terrano assumes that your transmitter is a vertically polarized (Z-directed) resonant half-wave dipole antenna. This antenna has an almost omni-directional radiation pattern in all azimuth directions. It also has radiation nulls along the axis of the dipole. You can change the direction of the dipole and orient it along the X or Y axes using the provided drop-down list. The second choice of two orthogonally polarized isotropic radiators is an abstract source that is used for polarimetric channel characterization as will be discussed later.  You can override the default radiator option and select any other kind of antenna with a more complicated radiation pattern. For this purpose, first you need to have at least one to import a radiation pattern data file to EM.Terrano. You can model any radiating structure using [[EM.Cube]]'s other computational modules, [[EM.Tempo]], [[EM.Picasso]], [[EM.Libera]] or [[EM.Illumina]], and generate a 3D radiation pattern data file for it. The far-field radiation patter data are stored in a specially formatted file with a "'''.RAD'''" file extension. This file contains columns of spherical φ and θ angles as well as the real and imaginary parts of the complex-valued far-zone electric field components '''E<sub>θ</sub>''' and '''E<sub>φ</sub>'''. The θ- and φ-components of the far-zone electric field determine the polarization of the transmitting radiator.  {{Note|By default, EM.Terrano assumes a vertical half-wave dipole radiator for your point transmitter set.}} A transmitter set always needs to be associated with an existing base location set with one or more point objects in your the project workspace. Follow the procedure belowTherefore, you cannot define a transmitter for your scene before drawing a point object under a base location set.  [[Image:Info_icon.png|40px]] Click here to learn how to define a '''[[Glossary_of_EM.Cube%27s_Materials,_Sources,_Devices_%26_Other_Physical_Object_Types#Point_Transmitter_Set | Point Transmitter Set]]'''.
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<td> [[Image:Terrano L1 Fig11.png|thumb|left|480px|The point transmitter set definition dialog.]] </td>
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Once you define a new transmitter set, its name is added in the '''Transmitters''' section of the navigation tree. The color of all the base points associated with the newly defined transmitter set changes , and an additional little ball with the transmitter color (red by default) appears at the location of each associated base point. You can open the property dialog of the transmitter set and modify a number of parameters including the '''Baseband Source Power''' in Watts and the broadcast signal '''Phase''' in degrees. The default transmitter power level is 1W OR or 30dBm. There is also a check box labeled '''Use Custom Input Power''', which is checked by default. In that case, the power and phase boxes are enabled and you can change the default 1W power and 0° phase values as you wish. [[EM.Cube]]'s ".RAD" radiation pattern files usually contain the value of "Total Radiated Power" in their file header. This quantity is calculated based on the particular excitation mechanism that was used to generate the pattern file in the original [[EM.Cube]] module. When the "Use Custom Input Power" check box is unchecked, EM.Terrano will use the total radiated power value of the radiation file for the SBR simulation. Â {{Note|In order to modify any of the transmitter set's parameters, first you need to select the "User Defined Antenna" option, even if you want to keep the vertical half-wave dipole as your radiator.}}
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[[File:Terrano L1 Fig13NewTxProp.png|thumb|left|480px720px|The property dialog of a point transmitter set.]]
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Your transmitter in EM.Terrano allows you to define Teranno is indeed more sophisticated than a simple radiator. It consists of a basic '''Heterodyne "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 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 transmitting transmit antenna characteristics are automatically filled from 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.}}
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<td> [[File:PROP20ANewTxChain.png|thumb|600pxleft|720px|EM.Terrano's Transmitter Chain point transmitter chain dialog.]] </td>
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=== Defining a Point Receiver Set in the Formal Way ===
[[File:PROP21(1).png|thumb|400px|EM.Terrano's preliminary Receiver dialog.]] [[File:PROP22.png|thumb|400px|EM.Terrano's Receiver dialog with an isotropic radiator selected.]] 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 fewSimilar to a transmitter, a typical propagation scene may involve receiver is a large number of receiverspoint radiator, too. EM. To generate Terrano gives you three options for the radiator associated with a wireless coverage map, you need to define an array of points as your base point receiver set. :
To define a receiver observable in EM.Terrano, follow the procedure below:* Half-wave dipole* Polarization matched isotropic radiator* User defined antenna pattern
* RightBy default, EM.Terrano assumes that your receiver is a vertically polarized (Z-click on directed) resonant half-wave dipole antenna. You can change the '''Receivers''' item direction of the navigation tree dipole and select '''Insert New Receiver Set...''' from orient it along the contextual menu. This opens of X or Y axes using the preliminary Receiver Set dialogprovided drop-down list.* Choose An isotropic radiator has a name perfect omni-directional radiation pattern in all azimuth and for your receiver setelevation directions. * From An isotropic radiator doesn't exist physically in the dropdown list labeled '''Associated Base real world, but it can be used simply as a point Set''', select in space to compute the desired set.* Click the {{key|OK}} button of the dialog to close itelectric field.
A new You may also define a complicated radiation pattern for your receiver set entry is added in the '''Receivers''' section of the navigation tree. After defining a receiver setIn that case, the base points associated with it change their color you need to import a radiation pattern data file to EM.Terrano similar to the receiver color, which is yellow by default. The first element case of the a transmitter set is represented by a larger ball of the same color indicating that it is the selected receiver in the scene.
The Receiver Set Dialog is also used to access individual receivers of the set for data visualization at the end of a simulation. At the end of an SBR simulation{{Note|By default, the button labeled "Show Ray Data" becomes enabledEM. Clicking this button opens the Ray Data Dialog, where you can see Terrano assumes a list of all the received rays at the selected vertical half-wave dipole radiator for your point receiver and their computed characteristicsset. }}
{{Note| EMSimilar to transmitter sets, you define a receiver set by associating it with an existing base location set with one or more point objects in the project workspace.Terrano All the receiversbelonging to the same receiver set have the same radiator type. A typical propagation scene contains one or few transmitters but usually a large number of receivers. To generate a wireless coverage map, by default, are defined you need to define an array of points as isotropic or polarization-matched radiatorsyour base location 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[[Image:Info_icon. 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 {{keypng|Import Pattern}} button. You can also rotate the imported radiation pattern by setting '''Rotation Angles''' different than the default zero values. EM.Terrano allows you 40px]] Click here to learn how to define a basic '''Heterodyne Receiver Chain'''[[Glossary_of_EM. Click the {{keyCube%27s_Simulation_Observables_%26_Graph_Types#Point_Receiver_Set |Receiver Chain}} button of the Point Receiver Set dialog to open the Receiver Chain dialog. As shown in the figure below, you can specify the characteristics of the Low-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 for antenna]]'s '''Brightness Temperature''' as well as the temperature of the transmission line and the 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 input. Â In the Receiver Set dialog, there is a dropdown list labeled "Selected Receiver", which contains a list of all the individual receivers belonging to the receiver set. At the end of an SBR simulation, the receiver power and signal-noise ratio (SNR) of the selected receiver are calculated and reported in dBm and dB, respectively. The {{key|Show Ray Data}} button also allows you to see the details of all the received rays by the selected receiver.
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<td> [[FileImage:PROP22ATerrano L1 Fig12.png|thumb|600pxleft|EM.Terrano's Receiver Chain 480px|The point receiver set definition dialog.]] </td>
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=== 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.
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<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>
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In the Receiver Set dialog, there is a drop-down list labeled '''Selected Element''', which contains a list of 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 list of all the received rays at the selected receiver and their computed characteristics.
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If you choose the "user defined antenna" option for your receiver set, it indeed consists of a basic "Receiver Chain" that contains a receive antenna connected via a segment of transmission line to the low-noise amplifier (LNA) that is terminated in a matched load. The receiver set's property dialog allows you to define the basic 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 LNA such as its gain and noise figure in dB 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 for antenna's '''Brightness Temperature''' as well as the temperature of the transmission line and the receiver's ambient temperature. The effective '''Receiver Bandwidth''' is assumed to be 100MHz, which you can change for the purpose of noise calculations. The Receive Chain dialog calculates and reports the "Noise Power" and "Total Receiver Chain Gain" based on your input. At the end of an SBR simulation, the receiver power and signal-noise ratio (SNR) of the selected receiver are calculated and they are reported in the receiver set dialog in dBm and dB, respectively. You can examine the properties of all the individual receivers and all the individual rays received by each receiver in your receiver set using the "Selected Element" drop-down list.
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<td> [[File:PROP22DNewRxChain.png|thumb|600pxleft|Rotating the dipole antenna by +90° about the local X-axis and then by -45° by the local Y-axis720px|EM.Terrano's point receiver chain dialog.]] </td>
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=== Adjustment of Tx/Rx Elevation above a Terrain Surface Modulation Waveform and Detection ===
When your transmitters or receivers are located above a flat terrain like the global ground, their Z-coordinates are equal to their height above the ground, as the terrain elevation is fixed and equal to zero everywhere. In many propagation modeling problems, your transmitters and receivers may be located above an irregular terrain with varying elevation across the scene. In that case, you may want to place your transmitters or receivers at a certain height above the underlying ground. The Z-coordinate of a transmitter or receiver is now the sum of the terrain elevation at the base point and the specified height. EM.Terrano gives allows you the option to adjust the transmitter and receiver sets to the terrain elevation. This is done define a digital modulation scheme for individual transmitter sets and individual receiver setsyour communication link. At the top of the Transmitter Dialog there is a check box labeled "'''Adjust Tx Sets There are currently 17 waveforms to Terrain Elevation'''". Similarly, at the top of the Receiver Dialog there is a check box labeled "'''Adjust Rx Sets to Terrain Elevation'''". These boxes are unchecked by default. As a result, your transmitter sets or receiver sets coincide with their associated base points choose from in the project workspace. If you check these boxes and place a transmitter set or a receiver set above an irregular terrain, the transmitters or receivers are elevated from the location of their associated base points by the amount of terrain elevation as can be seen in the figure below. property dialog:
To better understand why there are two separate sets of points in the scene, note that a point array *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 (CAD objectBT = 0.3) is used to create a uniformly spaced base set. The array object always preserves its grid topology as you move it around the scene. However, the transmitters or receivers associated with this point array object are elevated above the irregular terrain and no longer follow a strictly uniform grid. If you move the base set from its original position to a new location, the base points' topology will stay intact, while the associated transmitters or receivers will be redistributed above the terrain based on their new elevations.
<table><tr><td> [[Image:prop_txrx1_tnIn the above list, you need to specify the '''No.png|thumb|360px|Transmitter Levels (redM) and receivers (yellow) adjusted above an uneven terrain surface''' for the Mary modulation schemes, from which the '''No.]] </td><td> [[Image:prop_txrx2_tnBits per Symbol''' is determined.png|thumb|360px|The underlying base point sets (blue and orange dots) associated with You can also define a bandwidth for the adjusted transmitters and receivers on signal, which has a default value of 100MHz. Once the terrain.]] SNR of the signal is found, given the specified modulation scheme, the E</tdsub>b</trsub>/N<sub>0</tablesub>parameter is determined, from which the bit error rate (BER) is calculated.
== Defining Sources & Observables for Your SBR Simulation ==The Shannon â Hartley Equation estimates the channel capacity:
Like every other electromagnetic solver, EM.Terrano's SBR ray tracer requires an excitation source and one or more observables for generation of simulation data. EM.Terrano offers several types of sources and observables for a SBR simulation. You can mix and match different source types and observable types depending on the requirements of your modeling problem. The available source types are <math> C = B \log_2 \left(click on each type to learn more about it1 + \frac{S}{N} \right): </math>
* '''[[#Defining Transmitter Sets | Transmitter]]'''* '''[[#Defining_a_Hertzian_Dipole_Source | Hertzian Dipole]]'''where B in the bandwidth in Hz, and C is the channel capacity (maximum data rate) expressed in bits/s.
The available observables types are (click on each type to learn more about it):spectral efficiency of the channel is defined as
* '''[[#Defining Receiver Sets | Receiver]]'''* '''[[#Defining_a_Field_Sensor | Field Sensor]]'''* '''[[#Computing_Radiation_Patterns_In_SBR | Far Field Radiation Pattern]]'''* '''[[Hybrid_Modeling_using_Multiple_Simulation_Engines#Generating_Huygens_Surface_Data | Huygens Surface]]'''<math> \eta = \log_2 \left( 1 + \frac{S}{N} \right) </math>
A short dipole source The quantity E<sub>b</sub>/N<sub>0</sub> is the simplest type ratio of excitation for your propagation sceneenergy per bit to noise power spectral density. A short dipole has an almost "omni-directional" radiation pattern, and It is the closest thing to an isotropic radiator. EM.Terrano does not provide a theoretical/hypothetical isotropic transmitter because its SBR solver is fully polarimetric measure of SNR per bit and requires a real physical radiator for ray generation. A transmitter is a more sophisticated source that requires a base point as well as an imported radiation pattern file with a '''.RAD''' file extension.calculated from the following equation:
Of the above list of EM.Terrano's observables types, receivers are the ones you would typically use for your propagation scenes. Unlike a transmitter, a receiver by default does not require an imported radiation pattern file. A default receiver is assumed to be polarization<math> \frac{E_b}{N_0} = \frac{ 2^\eta -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 electromagnetic field solver. The Huygens surface observable is primarily used for [[Hybrid Modeling using Multiple Simulation Engines|hybrid modeling using multiple simulation engines]]. 1}{\eta} </math>
{{Note| In order to define either transmitters or receivers, first you have to define base pointswhere η is the spectral efficiency. For a transmitter, you additionally need to import a radiation pattern file from one of [[EM.Cube]]'s other computational modules.}}
== Using EMThe 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.Terrano as an Asymptotic Field Solver ==non-coherent). For example, for coherent QPSK modulation, one can write:
[[File:PROP18<math> P_b = 0.5 \; \text{erfc} \left(1\sqrt{ \frac{E_b}{N_0} } \right).png|thumb|350px|EM.Terrano's Short Dipole Source dialog.]] </math>The simplest SBR simulation can be performed using a short dipole source with a specified field sensor plane. As an asymptotic EM solver, EM.Terrano then computes where P<sub>b</sub> is the electric bit error rate and magnetic fields radiated by your dipole source in erfc(x) is 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.<!--[[Imagecomplementary error function:Info_icon.png|40px]] Click here to learn more about using EM.Terrano as an '''[[Asymptotic Field Solver]]'''.-->
<math> \text{erfc}(x) =1-\text{erf}(x) == Defining a Hertzian Dipole Source ===\frac{2}{\sqrt{\pi}} \int_{x}^{\infty} e^{-t^2} dt </math>
A short dipole The '''Minimum Required SNR''' parameter is used to determine link connectivity between each transmitter and receiver pair. If you check the simplest way box labeled '''Generate Connectivity Map''' in the receiver set property dialog, a binary map of exciting a structure in [[the propagation scene is generated by EM.Terrano]]. It is also , in which one color represents a closed link and another represent no connection depending on the closest thing to an omnidirectional radiator. The direction or orientation selected color map type of the short dipole determines its polarizationgraph. Note that EM.Terrano does not offer an isotropic radiator as a source type because also calculates the '''Max Permissible BER''' corresponding to the specified minimum required SNR and displays it is a polarimetric ray tracer. A short dipole source acts like an infinitesimally small ideal current source. A short dipole source appears as a small arrow in your scene. The total radiated power by your dipole source is calculated and displayed in Watts in its the receiver set property dialog.
[[Image:Info_icon=== A Note on EM.png|40px]] Click here to learn more about Terrano'''[[Common_Excitation_Source_Types_in_EM.Cube#Hertzian_Dipole_Sources | Hertzian s Native Dipole Sources]]'''.Radiators ===
=== Defining When you define a Field Sensor ===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[[File:PROP18\frac{\text{cos} \left(\frac{k_0 L}{2} \text{cos} \theta \right).png|thumb|350px|EM.Terrano's Field Sensor dialog- \text{cos} \left( \frac{k_0 L}{2} \right) }{\text{sin}\theta} \right]]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. </math>
Once you close the Field Sensor dialog<math> E_\phi(\theta, 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'''\phi) field as well as the total electric and magnetic fields.\approx 0 </math>
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. The directivity of the dipole antenna is given be the expression: <math> D_0 \approx \frac{2}{F_1(k_0L) + F_2(k_0L) + F_3(k_0L)} \left[\frac{\text{cos} \left( \frac{k_0 L}{2} \text{cos} \theta \right) - \text{cos} \left( \frac{k_0 L}{2} \right) }{\text{sin}\theta} \right]^2 </math> with  <math> F_1(x) = \gamma + \text{ln}(x) - C_i(x) </math> <math> F_2(x) = \frac{1}{2} \text{sin}(x) \left[Image:Info_icon.png|40pxS_i(2x) - 2S_i(x) \right]] Click here to learn more about ''' </math> <math> F_3(x) = \frac{1}{2} \text{cos}(x) \left[[Data_Visualization_and_Processing#Visualizing_3D_Near\gamma + \text{ln}(x/2) + C_i(2x) -Field_Maps | Visualizing 3D Near Field Maps2C_i(x) \right]]''' </math>  where γ = 0.5772 is the Euler-Mascheroni constant, and C<sub>i</sub>(x) and S<sub>i</sub>(x) are the cosine and sine integrals, respectively:  <math> C_i(x) = - \int_{x}^{\infty} \frac{ \text{cos} \tau}{\tau} d\tau </math> <math> S_i(x) = \int_{0}^{x} \frac{ \text{sin} \tau}{\tau} d\tau </math>  In the case of a half-wave dipole, L = λ<sub>0</sub>/2, and D<sub>0</sub> = 1.643. Moreover, the input impedance of the dipole antenna is Z<sub>A</sub> = 73 + j42.5 Ω. These dipole radiators are connected via 50Ω transmission lines to a 50Ω source or load. Therefore, there is always a certain level of impedance mismatch that violates the conjugate match condition for maximum power.
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<td> [[ImageFile:PROP18MDipole radiators.png|thumb|360px720px|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|360px|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>
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=== 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:Info_icon.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:Info_icon=== 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.
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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 free space 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 local Y-axis.]] </td></tr></table> === Adjustment of Tx/Rx Elevation above a Terrain Surface === When your transmitters or receivers are located above a flat terrain like the global ground, their Z-coordinates are equal to their height above the ground, as the terrain elevation is fixed and equal to 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 1GHza 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 figure below.  To better understand why there are two separate sets of points in the scene, note that a point array (CAD object) is used to create a uniformly spaced base set. The array object always preserves its grid topology as you move it around the scene. However, the transmitters or receivers associated with this point array object are elevated above the irregular terrain and no longer follow a strictly uniform grid. If you move the base set from its original position to a new location, the base points' topology will stay intact, while the associated transmitters or receivers will be redistributed above the terrain based on their new elevations. <table><tr><td> [[Image:PROP MAN8.png|thumb|left|640px|A transmitter (red) and a grid of receivers (yellow) adjusted above a plateau terrain surface. The underlying base point sets (blue and orange dots) associated with the adjusted transmitters and receivers on the terrain are also visible in the figure.]] </td>
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== Discretizing the Propagation Scene in EM.Terrano ==
=== Why Do You Need to Discretize the Scene? ===
EM.Terrano's SBR ray tracer solver uses a method known as Geometrical Optics (GO) in conjunction with the Uniform Theory of Diffraction (UTD) to traces trace the rays from their originating point at the source to the individual receiver locations. Ray Rays may hit obstructing objects on their way and get reflected, diffracted or transmitted. EM.Terrano's SBR solver can only handle diffraction off linear edges and reflection from and transmission through planar material interfaces. The underlying theory for calculation of reflection, transmission and diffraction coefficients indeed assumes material media of infinite extents. When a an incident ray hits a specular point on the surface of the obstructing object, a local planar surface assumption is made at the specular point. The assumptions of linear edges and planar facets obviously work in the case of a scene with cubic buildings and a flat global ground.
[[Image:Info_iconIn many practical scenarios, however, your buildings may have curved surfaces, or the terrain may be irregular. EM.png|40px]] Click here Terrano allows you to learn more about the theory 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'''[[SBR Method]]'''s mesh generator creates a triangular surface mesh of all the objects in your propagation scene, which is called a facet mesh. Even the walls of cubic buildings are meshed using triangular cells. This enables EM.Terrano to properly discretize composite buildings made of conjoined cubic objects.
If your propagation scene contains only cubic buildings on the flat global groundUnlike [[EM.Cube]]'s other computational modules, the assumptions density or resolution of linear edges and planar facets hold well although they violate the infinite extents assumptionEM. In many practical scenarios, however, your buildings may have curved Terrano's surface or mesh does not depend on the terrain may be irregularoperating frequency and is not expressed in terms of the wavelength. The sole purpose of EM.Terrano allows you 's facet mesh is to draw any type of surface or solid CAD objects under impenetrable and penetrable surface groups or penetrable volumes. Some of these objects contain discretize curved surfaces or curved boundaries and irregular scatterers into flat facets and linear edges such as cylinders, cones, etc. In order to address all such cases in the most general contextTherefore, EMgeometrical fidelity is the only criterion for the quality of a facet mesh.Terrano always uses It is important to note that discretizing smooth objects using a triangular surface mesh typically creates a large number of all small edges among the objects in your propagation scenefacets that are simply mesh artifacts and should not be considered as diffracting edges. Even For example, each rectangular facets face of a cubic buildings building is subdivided into four triangles along the two diagonals. The four internal edges lying inside the face are meshed using triangular cellsobviously not diffracting edges. This is done to A lot of subtleties like these must be able taken into account by the SBR solver to properly discretize composite buildings made of conjoined cubic objectsrun accurate and computationally efficient simulations.
=== Generating the SBR Facet Mesh ===
[[Image:prop_manual-29.png|thumb|350px|EM.TerranoYou can view and examine the discretized version of your scene's Mesh Settings dialogobjects as they are sent to the SBR simulation engine.]] Unlike [[EMYou can adjust the mesh resolution and increase the geometric fidelity of discretization by creating more and finer triangular facets.Cube]]'s On the other computational moduleshand, you may want to reduce the density or mesh complexity and send to the SBR engine only a few coarse facets to model your buildings. The resolution of EM.Terrano's surface facet mesh does not depend on generator is controlled by the operating frequency and '''Cell Edge Length''' parameter, which is not expressed in terms of the wavelengthproject length units. Its sole purpose is to discretize curved and irregular scatterers into The default mesh cell size of 100 units might be too large for non-flat facets and linear edgesobjects. Therefore, geometrical fidelity is the only criterion for the quality of an SBR mesh. It is important You may have to note that discretizing smooth objects using set 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 edgessmaller cell edge length in EM. For exampleTerrano's Mesh Settings dialog, each rectangular face of a cubic building is subdivided into four triangles along with a lower curvature angle tolerance value to capture the two diagonals. The four internal edges lying inside the face are obviously not diffracting edges. A lot curvature of subtleties like these must be taken into account by the SBR solver to run accurate and computationally efficient simulationsyour curved structures adequately.
You can view and examine the discretized version of your scene 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. Unlike <table><tr><td> [[EM.Cube]]'s other computational modules that express the default mesh density based on the wavelength, the resolution of the SBR mesh generator is controlled by the '''Mesh Cell Size''' parameter, which is expressed in project length units. The default mesh cell size of 100 units might be too large for nonImage:prop_manual-flat objects29. You may have to set a smaller mesh cell size in png|thumb|left|480px|EM.Terrano's Mesh Settings mesh settings dialog, along with a lower curvature angle tolerance value to capture the curvature of your curved structures adequately.]] </td></tr></table>
[[Image:Info_icon.png|40px30px]] Click here to learn more about '''[[Mesh_Generation_Schemes_in_EMPreparing_Physical_Structures_for_Electromagnetic_Simulation#Working_with_EM.Cube#Working_with_Mesh_Generator .27s_Mesh_Generators | Working with Mesh Generator ]]'''.
[[Image:Info_icon.png|40px30px]] Click here to learn more about [[EM.Cube]]'s the properties of '''[[Mesh_Generation_Schemes_in_EMGlossary_of_EM.Cube%27s_Simulation-Related_Operations#The_Triangular_Surface_Mesh_Generator Facet_Mesh | Triangular Surface EM.Terrano's Facet Mesh Generator]]'''.
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<td> [[Image:PROP15BUrbanCanyon2.png|thumb|550pxleft|640px|The brick facet mesh of the buildings in an the urban propagation scenegenerated by EM.Terrano's Random City wizard with a cell edge length of 100m.]] </td>
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<td> [[Image:PROP15CUrbanCanyon3.png|thumb|550pxleft|640px|The triangular surface facet mesh of the building buildings in the urban propagation scenegenerated by EM.Terrano's Random City wizard with a cell edge length of 10m.]] </td>
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== Running SBR 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 SolverOnce 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 ray tracing simulation. EM.Terrano offers thee simulation modes (click on each type to learn more about it): * SBR Channel Analyzer* Log-Haul Channel Analyzer* Communication Link Solver* Radar Link Solver
* '''[[#Running a Single-Frequency SBR Analysis | Single-Frequency Analysis]]'''* '''[[Parametric_Modeling,_Sweep_%26_Optimization#Running_Frequency_Sweep_Simulations_in_EM.Cube | Frequency Sweep]]''' * '''[[Parametric_Modeling,_Sweep_%26_Optimization#Running_Parametric_Sweep_Simulations_in_EM.Cube | Parametric Sweep]]'''Â You can set the simulation mode from EM.Terrano's "Simulation Run Dialog". A single-frequency analysis is a single-run simulation. The two other first three simulation modes in the above list types are considered multi-run simulationsdescribed below. If you run For a simulation without having defined any observables, no data will be generated at the end description of the simulation. In multi-run simulation modes, certain [[parameters]] are varied and a collection of simulation data files are generated. At the end of a sweep simulation, you can graph the simulation results in EM.Grid or you can animate the 3D simulation data from the navigation tree. Â {{Note| EM.Terrano's frequency sweep simulations are very fast because the geometrical optics (ray tracing) part of the simulation is frequency-independentRadar Simulator, follow this link.}}
=== Running a Single-Frequency SBR 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 and in EM.Terrano. It involves the following steps:
* Set the units of your project and the frequency of operation. Note that the default project unit is '''millimeter'''. Wireless propagation problems usually require meter, mile or kilometer as the project unit.
* 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.
== Working with 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 Simulation Data ==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.
=== EM.Terrano's Output Simulation Data ===gives a few more options for the ray tracing solution of your propagation problem. For instance, it allows you to exclude the direct line-of-sight (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 also allows you to superpose the received rays incoherently. In that case, the powers of individual ray are simply added to compute that total received power. This option in the check box labeled "Superpose rays incoherently" is disabled by default, too.
At the end of an SBR a ray tracing simulation, all the polarimetric rays emanating from the transmitter(s) or other sources that are received by the electric field of each individual receivers are ray is computed, collected, sorted and savedreported. From By default, the actual received ray datafields are reported, which are independent of the total electric field at the location radiation pattern of receivers as well as the received power are computedreceive antennas. The ray data include the field components of each ray, the EM.Terrano provides a check box labeled "Normalize ray's elevation and azimuth angles of departure and arrival (departure from the transmitter location and arrival at the E-field based on receiver location)pattern", and time delay of the received ray with respect to the transmitterwhich is unchecked by default. If you specify the temperaturethis box is checked, noise figure levels and transmission line losses in the definition field of each ray is normalized so as to reflect that effect of the receiver sets, the noise antenna's radiation pattern. The received power level and signal-to-noise ratios (SNR) at of each receiver are also ray is 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. from the following equation:
<math> P_{ray} === Visualizing Field & Received Power Coverage Maps ===\frac{ | \mathbf{E_{norm}} |^2 }{2\eta_0} \frac{\lambda_0^2}{4\pi} </math>
As an asymptotic EM simulator, EM.Terrano computes It can be seen that if the polarimetric electric ray's E-field at every receiver location including amplitude and phase of all three Xis not normalized, Y, Z field components as well as the total field magnitude. In wireless propagation modeling for communication system applications, the received computed ray power at the receiver location is more important than the field values. Wireless coverage maps commonly refer will correspond to the received power levels at different locations in that of a given sitepolarization matched isotropic receiver. 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.* '''=== Polarimetric 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.Analysis ===
In a 3D SBR simulation, a transmitter shoots a large number of rays in all directions. The received power P<sub>r</sub> 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 dBm is found the propagation scene and bounce from the following equation: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 '''E<mathsub> P_r [dBm] = P_t [dBm] + G_{TC} + G_{TA} - PL + G_{RA} + G_{RC} θ</mathsub>''' and '''E<sub>φ</sub>''' field components associated with each ray at the receiver location to its '''E<sub>θ</sub>''' and '''E<sub>φ</sub>''' field components at the transmitter location. Each ray has a delay and θ and φ angles of departure at the transmitter location and θ and φ angles of departure at the receiver location.
where P<sub>t</sub> is the baseband signal power in dBm at the transmitterTo perform a polarimatric channel characterization of your propagation scene, G<sub>TC</sub> open EM.Terrano's Run Simulation dialog and G<sub>RC</sub> are select '''Channel Analyzer''' from the total transmitter and receiver chain gains in dB, respectively, G<sub>TA</sub> and G<sub>RA</sub> are drop-down list labeled '''Select Simulation or Solver Type'''. At the total transmitting and receiving antenna gains in dBend of the simulation, respectively, and PL a large ray database is the channel path loss in dBgenerated with two data files called "sbr_channel_matrix. Keep in mind that EMDAT" and "sbr_ray_path.Terrano is fully polarimetricDAT". The transmitting and receiving antenna characteristics are specified through former file contains the imported radiation pattern filesdelay, which are part angles of the definition arrival and departure and complex-valued elements of the transmitters channel matrix for all the individual rays that leave each transmitter and receiversarrive at each receiver. In particular, The latter file contains the polarization mismatch losses are taken into account through the polarimetric SBR geometric aspects of each ray tracing analysissuch as hit point coordinates.
EM.Terrano's transmitters always require 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=== The "Near Real-matched to the incoming rays. As such, they have a unity gain and do not exhibit any polarization mismatch losses. Time" Polarimatrix Solver ===
At After EM.Terrano's channel analyzer generates a ray database that characterizes your propagation channel polarimetrically for all the end combinations of an SBR simulationtransmitter and receiver locations, you a ray tracing solution of the propagation problem can visualize readily be found in almost real time by incorporating the field maps and receiver power coverage map effects of your receiver setsthe radiation patterns of transmit and receive antennas. A coverage map shows This is done using the total '''Received PowerPolarimatrix Solver''' by each of the receivers and , which is visualized as a color-coded intensity plot. Under each receiver set node in the navigation tree, a total third option 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 drop-down list labeled '''Select Simulation or coverage map, simply click on its entry Solver Type''' in the navigation treeEM. 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)Terrano's Run Simulation dialog. The 3D coverage maps are displayed as horizontal confetti above the receivers. You can change the appearance results of the receivers Polarimatrix and maps 3D SBR solvers must be identical from the property dialog a theoretical point of the receiver setview. You can further customize However, there might be small discrepancies between the settings of the 3D field and coverage plotstwo solutions due to roundoff errors.
[[Image:Info_icon.png|40px]] Click here Using the Polarimatrix solver can lead to learn more about '''[[Data_Visualization_and_Processing#Visualizing_3D_Near-Field_Maps | Visualizing 3D Near-Field Maps]]'''a significant reduction of the total simulation time in sweep simulations that involve a large number of transmitters and receivers. Certain simulation modes of EM.Terrano are intended for the Polarimatrix solver only as will be described in the next section.
At {{Note| In order to use the end of a frequency sweep or parametric sweep SBR simulationPolarimatrix solver, as many coverage maps as the number of sweep variable samples are generated and added to the navigation tree. In this case the additional seven field maps are saved to avoid you must first generate a cluttered navigation tree. You can click on each ray database of the coverage maps corresponding to each of the variable samples and visualize it in the project workspaceyour propagation scene using EM. You can also animate the coverage maps on the navigation treeTerrano's Channel Analyzer.}}
=== EM.Terrano'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;" | [[Image#Running a Single-Frequency SBR Analysis | Single-Frequency Analysis]]| style="width:Info_icon180px;" | 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.pngCube#Running_Frequency_Sweep_Simulations_in_EM.Cube |40pxFrequency Sweep]] | style="width:180px;" | Varies the operating frequency of the ray tracer | style="width:150px;" | SBR, Channel Analyzer, Polarimatrix, Radar Simulator| style="width:120px;" | Runs at a specified set of frequency samples| style="width:300px;" | None|-| style="width:120px;" | [[Parametric_Modeling_%26_Simulation_Modes_in_EM.Cube#Running_Parametric_Sweep_Simulations_in_EM.Cube | Parametric Sweep]]| style="width:180px;" | Varies the value(s) of one or more project variables| style="width:150px;" | SBR| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires definition of sweep variables, works only with SBR solver as the physical scene may change during the sweep |-| style="width:120px;" | [[#Transmitter_Sweep | Transmitter Sweep]]| style="width:180px;" | Activates two or more transmitters sequentially with only one transmitter broadcasting at each simulation run | style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires at least two transmitters in the scene, works only with Polarimatrix solver and requires an existing ray database|-| style="width:120px;" | [[#Rotational_Sweep | Rotational Sweep]]| style="width:180px;" | Rotates the radiation pattern of the transmit antenna(s) sequentially to model beam steering | style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Works only with Polarimatrix solver and requires an existing ray database|-| style="width:120px;" | [[#Mobile_Sweep | Mobile Sweep]]| style="width:180px;" | Considers one pair of active transmitter and receiver at each simulation run to model a mobile communication link| style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires the same number of transmitters and receivers, works only with Polarimatrix solver and requires an existing ray database|} Click here 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'''[[Data_Visualization_and_Processing#3D_Near_.26_Far_Field_Animation | Animating A single-frequency analysis 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 files are generated. At the end of a sweep simulation, you can plot the output parameter results on 2D graphs or you can animate the 3D Nearsimulation data 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-Field Mapsindependent.}} === Transmitter Sweep === When your propagation scene contains two or more transmitters, whether they all belong to the same transmitter set with the same radiation pattern or to different transmitter sets, EM.Terrano assumes all to be coherent with respect to one another. In other words, synchronous transmitters are always assumed. The rays originating from all these transmitters are superposed coherently and vectorially at each receiver. In a transmitter sweep, on the other hand, EM.Terrano assumes only one transmitter broadcasting at a time. The result of the sweep simulation is a number of received power coverage maps, each corresponding to a transmitter in the scene. {{Note| EM.Terrano's transmitter sweep works only with the Polarimatrix Solver and requires an existing ray database previously generated using the Channel Analyzer.}} === Rotational Sweep === 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. {{Note| EM.Terrano's rotational sweep works only with the Polarimatrix Solver and requires an existing ray database previously generated using the Channel Analyzer.}} === Mobile Sweep === In a mobile sweep, each transmitter is paired with a receiver according to their indices in their parent sets. At each simulation run, only one (Tx, Rx) pair is considered to be active in the scene. As a result, the generated coverage map takes a different meaning implying the sequential movement of the transmitter and receiver pair along their corresponding paths. In other words, the set of point transmitters and the set of point receivers indeed represent the locations of a single transmitter and a single receiver at different instants of time. It is obvious that the total number of transmitters and total number of receivers in the scene must be equal. Otherwise, EM.Terrano will prompt an error message. [[EM.Cube]]provides a '''Mobile Path Wizard''' that facilitates the creation of a transmitter set or a receiver set along a specified path. This path can be an existing nodal curve (polyline or NURBS curve) or an existing line objects. You can also import a sptial Cartesian data file containing the coordinates of the base location points. For more information, refer to [[Glossary_of_EM.Cube%27s_Wizards#Mobile_Path_Wizard | Mobile Path Wizard]]. {{Note| EM.Terrano's mobile sweep works only with the Polarimatrix Solver and requires an existing ray database previously generated using the Channel Analyzer.}} === Investigating Propagation Effects Selectively One at a Time === In a typical SBR ray tracing simulation, EM.Terrano includes all the propagation effects such as direct (LOS) rays, ray reflection and transmission, and edge diffractions. At the end of a SBR simulation, you can visualize the received power coverage map of your propagation scene, which appears under the receiver set item in the navigation tree. The figure below shows the received power coverage map of the random city scene with a vertically polarized half-wave dipole transmitter located 10m above the ground and a large grid of vertically polarized half-wave dipole receivers placed 1.5m above the ground. The legend box shows the limits of the color map between -23dBm as the maximum and -150dB (the default receiver sensitivity value) as the minimum.
<table>
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<td> [[Image:prop_run11_tnUrbanCanyon10.png|thumb|550pxleft|Received 640px|The received power coverage map of an urban propagation the random city scenewith a dipole transmitter.]] </td>
</tr>
</table>
Â
Sometime it is helpful to change the scale of the color map to better understand the dynamic range of the coverage map. If you double-click on the legend or right-click on the coverage map's name in the navigation tree and select '''Properties''', the Plot Settings dialog opens up. Select the '''User-Defined''' item and set the lower and upper bounds of color map as you wish.
Â
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<td> [[Image:prop_run12_tnUrbanCanyon15.png|thumb|550pxleft|Total electric field 480px|The plot settings dialog of the coverage map.]] </td></tr></table><table><tr><td> [[Image:UrbanCanyon16.png|thumb|left|640px|The received power coverage map of an urban propagation the random city scenewith a user-defined color map scale between -80dBm and -20dBm.]] </td>
</tr>
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=== Calculating To better understand the SNR & Visualizing Connectivity Maps===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.
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<subtable>r</subtr> - P<subtd>n</sub>, where P<sub>n</sub> is the noise power level in dB[[Image:UrbanCanyon14. 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 thresholdpng|thumb|left|640px|EM. In other words, Terrano's simulation run dialog showing the SNR at the receiver must be greater than a certain specified minimum SNR levelcheck boxes for controlling various propagation effects. You specify (SNR)]] <sub/td>min</subtr></table> 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.
<table>
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<td> [[Image:PROP15AUrbanCanyon11.png|thumb|550pxleft|640px|The connectivity received power coverage map of an urban propagation the random city scene with direct LOS rays only.]] </td></tr><tr><td> [[Image:UrbanCanyon12.png|thumb|left|640px|The received power coverage map of the random city scene with reflected rays only.]] </td></tr><tr><td> [[Image:UrbanCanyon13.png|thumb|left|640px|The received power coverage map of the random city scene with diffracted rays only.]] </td></tr></table> == Working with EM.Terrano's Simulation Data == === The Ray Tracing Solvers' Output Simulation Data === Both the SBR solver and the Polarimatrix solver perform the same type of simulation but in two different ways. The SBR solver discretizes the scene including all the buildings and terrain, shoots a large number of rays from the transmitters and collects the rays at the receivers. The Polarimatrix solver does the same thing using an existing polarimetric ray database that has been previously generated using EM.Terrano's Channel Analyzer. It incorporates the effects of the radiation patterns of the transmit and receive antennas in conjunction with the polarimetric channel characteristics. At the end of a ray tracing simulation, all the polarimetric rays emanating from the transmitter(s) or other sources that are received by the individual receivers are computed, collected, sorted and saved into ASCII data files. From the ray data, the total electric field at the location of receivers as well as the total received power are computed. The individual ray data include the field components of each ray, the ray's elevation and azimuth angles of departure and arrival (departure from the transmitter location and arrival at the receiver location), and time delay of the received ray with respect to the transmitter. If you specify the temperatures, noise figure and transmission line losses in the definition of the receiver sets, the noise power level and signal-to-noise ratio (SNR) at each receiver are also calculated, and so are the E<sub>b</sub>/N<sub>0</sub> and bit error rate (BER) for the selected digital modulation scheme. === Visualizing Field & Received Power Coverage Maps === In wireless propagation modeling for communication system applications, the received power at the receiver location is more important than the field distributions. In order to compute the received power, you need three pieces of information: * '''Total Transmitted Power (EIRP)''': This requires knowledge of the baseband signal power, the transmitter chain parameters, the transmission characteristics of the transmission line connecting the transmitter circuit to the transmitting antenna and the radiation characteristics of the transmitting antenna.* '''Channel Path Loss''': This is computed through SBR simulation. * '''Receiver Properties''': This includes the radiation characteristics of the receiving antenna, the transmission characteristics of the transmission line connecting the receiving antenna to the receiver circuit and the receiver chain parameters. In a simple link scenario, the received power P<sub>r</sub> in dBm is found from the following equation: <math> P_r [dBm] = P_t [dBm] + G_{TC} + G_{TA} - PL + G_{RA} + G_{RC} </math> where P<sub>t</sub> is the baseband signal power in dBm at the transmitter, G<sub>TC</sub> and G<sub>RC</sub> are the total transmitter and receiver chain gains in dB, respectively, G<sub>TA</sub> and G<sub>RA</sub> are the total transmitting and receiving antenna gains in dB, respectively, and PL is the channel path loss in dB. Keep in mind that EM.Terrano is fully polarimetric. The transmitting and receiving antenna characteristics are specified through the imported radiation pattern files, which are part of the definition of the transmitters and receivers. In particular, the polarization mismatch losses are taken into account through the polarimetric SBR ray tracing analysis.  If you specify the noise-related parameters of your receiver set, the signal-to-noise ratios (SNR) is calculated at each receiver location: SNR = P<sub>r</sub> - P<sub>n</sub>, where P<sub>n</sub> is the noise power level in dB. When planning, designing and deploying a communication system between points A and B, the link is considered to be closes and a connection established if the received signal power at the location of the receiver is above the noise power level by a certain threshold. In other words, the SNR at the receiver must be greater than a certain specified minimum SNR level set . 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 25dBthe navigation tree underneath the received power coverage map node.  At the end of an SBR simulation, you can visualize the field maps and receiver power coverage map of your receiver sets. A coverage map shows the total '''Received Power''' by each of the receivers and is visualized as a color-coded intensity plot. Under each receiver set node in the navigation tree, a total of seven field maps together with a received power coverage map are added. The field maps include amplitude and phase plots for the three X, Y, Z field components plus a total electric field plot. To display a field or coverage map, simply click on its entry in the navigation tree. The 3D plot appears in the Main Window overlaid on your propagation scene. A legend box on the right shows the color scale and units (dB). The 3D coverage maps are displayed as horizontal confetti above the receivers. You can change the appearance of the receivers and maps from the property dialog of the receiver set. You can further customize the settings of the 3D field and coverage plots.  <table><tr><td>[[Image:AnnArbor Scene1.png|thumb|left|640px|The downtown Ann Arbor propagation scene.]]</td></tr><tr><td>[[Image:AnnArbor Scene2.png|thumb|left|640px|The electric field distribution map of the Ann Arbor scene with vertical dipole transmitter and receivers.]]</td></tr><tr><td>[[Image:AnnArbor Scene3.png|thumb|left|640px|The received power coverage map of the Ann Arbor scene with vertical dipole transmitter and receivers.]]</td></tr><tr><td>[[Image:AnnArbor Scene4.png|thumb|left| 640px |The connectivity map of the Ann Arbor scene with SNR<sub>min</sub> = 3dB with the basic color map option.]]</td></tr><tr><td>[[Image:AnnArbor Scene5.png|thumb|left| 640px |The connectivity map of the Ann Arbor scene with SNR<sub>min</sub> = 20dB with the basic color map option.]] </td>
</tr>
</table>
=== Visualizing the Rays in the Scene ===
[[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'''.
* 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.]]
</td>
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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).
<table>
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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></tr><tr><td> [[Image:prop_run6_tn.png|thumb|550px|Analyzing a selected ray from in the ray data dialograndom city scene.]] </td>
</tr>
</table>
=== 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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<table>
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<td>
[[Image:prop_run8_tn.png|thumb|left|720px|A typical SBR output data file.]]
</td>
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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_Files_in_Data_ManagerThe_Data_Manager | Data Manager]]'''.
<table>
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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>
</tr>
<tr>
<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|360pxleft|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|360px|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#Product_Overview | Back to the Top of the Page]]'''
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