Ensuring Accurate Broadband EM Analysis with Allegro PCB Designer
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Select OK in the EM ports dialog box to create the EM simulation structure with the pre-defined ports 1 and 2. To open the 3D
EM Layout view, select the EM structures in the EM structures folder in the project manager and select View 3D EM Layout
(Figure 10).
Figure 10: 3D EM Layout view
The original Allegro PCB board file contained four metal layers, but only layers 1 and 2 have been imported into the AWR
Design Environment platform. The length of the via that extend below the metal of layer 2 provides an indication that the
Allegro layout file has been successfully imported. It should be noted that the PCB layer stack information does not have to be
reentered after the IPC-2581-B file is imported, provided that the Allegro PCB Designer cross-section contained all the
required PCB stackup data (thickness of each layer, permittivity, conductivity).
The renamed EM port labels 1 and 2 are now correctly displayed in the AWR AXIEM 2D and 3D views and their properties can
be verified or edited by first selecting a port in the 2D view, followed by a right mouse click (RMB) -> Shape Properties (or
double click on the port). The port types will be assigned with the auto property per default.
For this example, the auto property can be left unchanged since the EM simulation is set up as a two-layer board, where layer
2 is a dedicated ground plane. For EM structures that utilize more layers, these port properties must be accurately set to
reflect the correct ground reference of each port.
To generate the mesh for this EM structure, first specify the frequency range for the EM simulation. Set the frequency range
to 1-6001MHz with 100MHz steps under the options setting of the EM structure in the project manager (Figure 11). Select
Mesh from the project manager (RMB on the desired EM structure), as shown in Figure 11 (right). This will produce the result
shown in Figure 12.
Figure 11: Options setting of the EM structure in the project manager (left) and project manager showing mesh selection (right)
Figure 12: Mesh of the EM structure in AWR AXIEM software
