Click here to learn more about using EM.Terrano as a [[Asymptotic Field Solver]].
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=== Hertzian Dipole Source ===
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[[File:PROP18(1).png|thumb|[[Propagation Module]]'s Transmitter dialog with a short dipole radiator selected]]
Earlier versions of [[EM.Cube]]'s [[Propagation Module]] used to offer an isotropic radiator with vertical or horizontal polarization as the simplest transmitter type. This release of [[EM.Cube]] has abandoned isotropic radiator transmitters because they do not exist physically in a real world. Instead, the default transmitter radiator type is now a Hertzian dipole. Note that before defining a transmitter, first you have to define a base set to establish the location of the transmitter. Most simulation scenes involve only a single transmitter. Your base set can be made up of a single point for this purpose.
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To define a new Transmitter Set, go to the '''Sources''' section of the Navigation Tree, right click on the '''Transmitters''' item and select '''Insert Transmitter...''' A dialog opens up that contains a default name for the new Transmitter Set as well as a dropdown list labeled '''Select Base Set'''. In this list you will see all the available base sets already defined in the project workspace. Select the desired base set to associate with the transmitter set. Note that if the base set contains more than one point, then more than one transmitter will be created and contained in your transmitter set. After defining a transmitter set, the base points change their color to the transmitter color, which is red by default.
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In the "Radiator" section of the dialog, you have two options to choose from: "Short Dipole" and "User Defined". The default option is short dipole. A short dipole radiator has a '''Length'''''dl'' expressed in project units, a current '''Amplitude''' in Amperes and a current '''Phase''' in degrees. The '''Direction''' of the dipole is determined by its unit vector that has three X, Y and Z components. By default, a Z-directed short dipole radiator is assumed. You can change all [[parameters]] of the dipole as you wish. Keep in mind that all the transmitters belonging to the same set have parallel radiators with identical properties.
=== Defining Base Point Sets ===
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.
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=== Defining Field Sensors ===
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[[File:PMOM90.png|thumb|[[Propagation Module]]'s Field Sensor dialog]]
As an asymptotic electromagnetic field solver, the SBR simulation engine can compute the electric and magnetic field distributions in a specified plane. In order to view these field distributions, you must first define field sensor observables before running the SBR simulation. To do that, right click on the '''Field Sensors''' item in the '''Observables''' section of the Navigation Tree and select '''Insert New Observable...'''. The Field Sensor Dialog opens up. At the top of the dialog and in the section titled '''Sensor Plane Location''', first you need to set the plane of field calculation. In the dropdown box labeled '''Direction''', you have three options X, Y, and Z, representing the"normals" to the XY, YZ and ZX planes, respectively. The default direction is Z, i.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.
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In the section titled Output Settings, you can also select the field map type from two options: '''Confetti''' and '''Cone'''. The former produces an intensity plot for field amplitude and phase, while the latter generates a 3D vector plot. In the confetti case, you have an option to check the box labeled '''Data Interpolation''', which creates a smooth and blended (digitally filtered) map. In the cone case, you can set the size of the vector cones that represent the field direction. At the end of a sweep simulation, multiple field map are produced and added to the Navigation Tree. You can animate these maps. However, during the sweep only one field type is stored, either the E-field or H-field. You can choose the field type for multiple plots using the radio buttons in the section titled '''Field Display - Multiple Plots'''. The default choice is the E-field.
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Once you close the Field Sensor dialog, its name is added under the '''Field Sensors''' node of the Navigation Tree. At the end of a SBR simulation, the field sensor nodes in the Navigation Tree become populated by the magnitude and phase plots of the three vectorial components of the electric ('''E''') and magnetic ('''H''') field as well as the total electric and magnetic fields defined in the following manner:
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:<math> \mathbf{|E_{tot}|} = \sqrt{|E_x|^2 + |E_y|^2 + |E_z|^2} </math>
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:<math> \mathbf{|H_{tot}|} = \sqrt{|H_x|^2 + |H_y|^2 + |H_z|^2} </math>
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=== Computing Radiation Patterns In SBR ===
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Coming Soon...
== Scene Discretization & Adjustment ==