Changes

EM.Terrano

520 bytes added, 20:35, 24 July 2015
/* The Field & Received Power Coverage Maps */
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. To adjust the mesh resolution, open the Mesh Settings Dialog by clicking the '''Mesh Settings''' [[File:mesh_settings.png]] button of the Simulate Toolbar or select '''Simulate > Discretization >''' '''Mesh Settings...'''. This dialog provides a single [[parameters]]: '''Edge Mesh Cell Size''', which has a default value of 100 project units. If you are already in the Mesh View Mode and open the Mesh Settings Dialog, you can see the effect of changing the mesh cell size using the {{key|Apply}} button.
Some additional mesh [[parameters]] can be accessed by clicking the {{key|Tessellation Options}} button of the dialog. In the Tessellation Options dialog, you can change the '''Curvature Angle Tolerance''' expressed in degrees, which has a default value of 45°. This parameter can affect the shape of the mesh especially in the case of [[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|solid objects]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]] with curved surfaces. Note that unlike [[EM.Cube]]'s other computational modules that express the default mesh density based on the wavelength, the resolution of the SBR mesh generator is expressed in project length units. The default mesh cell size of 100 units might be too large for non-flat objects. You may have to use a smaller mesh cell size along with a lower curvature angle tolerance value to capture the curvature of your curved structures adequately.
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=== The Field & Received Power Coverage Maps ===
As an asymptotic EM simulator, EM.Terrano computes the polarimetric electric field at every receiver location including amplitude and phase of all three X, Y, Z field components as well as the total field magnitude. In wireless propagation modeling for communication system applications, the received power at the receiver location is more important than the field values. Wireless coverage maps commonly refer to the received power levels at different locations in a given site. In order to compute the received power, you need the total transmitted power three pieces of information: * '''Total Transmitted Power (EIRP)''': This requires knowledge of the baseband signal power, path lossthe transmitter chain [[parameters]], the transmission characteristics of the transmission line connecting the transmitter circuit to the transmitting antenna and the radiation characteristics of the receiver transmitting antenna. More specifically, a number * '''Channel Path Loss''': This is computed through SBR simulation. * '''Receiver Properties''': This includes the radiation characteristics of receiver [[parameters]] including the receiving antenna, the transmission characteristics of the transmission line connecting the receiving antenna to the receiver circuit are also neededand the receiver chain [[parameters]].  The received power is found from the following equation: <math> P_r [dB] = P_t [dB] + G_{TC} + G_{TA} - PL + G_{RA} + G_{RC} </math>
If the associated radiator set is isotropic, so will be the transmitter set. By default, an isotropic transmitter has vertical polarization. You can use the '''Polarization''' radio button to select one of the two options: '''Vertical''' or '''Horizontal'''. If the associated radiator set consists of '''Short Dipole''' or '''User Defined''' radiators, it is indicated in the transmitter property dialog. In the case of a short dipole radiator, you can set a value for the dipole current in Amperes. The radiation resistance of a short dipole of length ''dl'' is given by:
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