PCB

Importing the layout

The project will open ready to import the PCB.

1. Open the 5g_test_board instance of the PCB Import Wizard.
2. Click on Import Format and note that the wizard supports both ODB++ and IPC-2581 files.
3. Click through the tabs to show the control of which layers import, which nets import, and how the STACKUP imports.
   • STACKUP verification is important as often PCB export data doesn't contain the proper electrical properties.
4. Press OK and the entire PCB will import and create a new Circuit Schematic called 5G_Test_Board

Cutting out the RF Region of Interest

Switches to already imported board to facilitate net selection.

1. Run the PCB EM Setup Wizard and choose Restore to restore the pin selection. Normally pin/net selection is done by the user but it was pre-saved in this example to make it easier to demo.
2. Choose Smart Select to select the traces connected to these pins.
3. Choose Smart Set Up to automatically create a ready to simulate EM Structure.
   • Choose Yes in the Create EM Clip Region dialog.
   • Choose Bounding Box and enter 2000um for the offset and click Preview then OK in the Create EM Clip Region Dialog
   • Choose Yes in the Layer Visibility Info dialog.
   • Choose OK in the Simplification Properties Info dialog.
   • Ensure AWR AXIEM - Async is the simulator and choose Create in the New EM Structure dialog.
   • Choose OK in the Simplification Properties dialog.
   • Choose Yes in the Cleanup Extra Shapes dialog.
4. The layout processing and adding ports will take a few seconds but when complete you'll see a new EM structure with ports added to the pins that were selected in the Circuit Schematic layout.
   • Note: The ports are a new port type called Point Ports and automatically position themselves in the middle of PCB pins.
5. Close the PCB EM Setup Wizard by choosing OK in the Wizard
6. Note that you just imported a complex board, selected a few nets and pins, and created a ready to simulate EM Structure of the simplified board in a couple of minutes!!

Viewing a better mesh for PCBs

Opens a v13 and v14 mesh of the EM structures for comparison

1. Click the Show 3D Mesh toolbar button for each structure to see the mesh.
2. Click information under each structure and compare the mesh count.
3. EM simulation time for PCBs is significantly faster with a smarter, simpler, mesh of the structure. Unknown counts in areas that do not impact the circuit performance as much (e.g. ground and/or power planes) are greatly reduced.

Using EM Structures in Circuit Schematics

With imported PCB data the component pin ids (e.g. C13.1, R24.2, etc.) are preserved on the EM Structure subcircuit symbol when the EM Structure is placed in a Circuit Schematic. In addition, layout look alike symbols help understand where the components go in the design. These two features make it easier to connect the components to the EM Structure.

Opens a Circuit Schematic window that contains an instance of the PCB EM Structure.

1. Note the layout look-alike symbol.
2. Zoom in on one of the pin locations and note the component pin IDs.

Importing PCB Data

The project will open and show the imported PA board layout, an EM structure created from the imported layout, and simulation results. Unfortunately this public domain demo board is not an RF or microwave design. We're working on finding a more realistic example, but, in the meantime, this board is sufficient for showing the PCB import flow.

The optional steps below provide more detail on PCB import and setting up the EM structure from the imported data by walk through re-creating the data in this project. Alternatively, you may want to just look around the project as it stands and not worry about the detailed steps.

PCB Import Wizard

Closes all the open windows so that there is no clutter during the import process.

1. Open the cds_routed instance of the PCB Import Wizard.
2. Click on Import Format and note that the wizard supports both ODB++ and IPC-2581 files.
3. Click through the tabs to show the control of which layers import, which nets import, and how the STACKUP imports.
• STACKUP verification is important as often PCB export data doesn't contain the proper electrical properties.
4. Press OK and the entire PCB will import and create a new Circuit Schematic called cds_routed

Selecting Nets and Configuring EM Clip Region

Entire nets can be selected by clicking on a shape in the layout, right clicking, and choosing Select By Name or with Edit > Select By Name. This example uses the latter approach.

1. Choose Edit > Select By Name.
2. Filter the list by typing RA in the filter field.
3. Select RA6 and RA0 (use ctrl for multi-select).
4. Select Preview.
5. Note the two selected nets near the top of the board.
6. Close the Select Net By Name dialog by choosing OK.

EM Clip Regions (i.e. cutting out area around the nets) are auto-defined as a bounding boxes, convex hull, or concave hull with an expansion distance by choosing Draw > Create EM Clip Region or by drawing any shape and converting it to an EM Clip Region. This example doesn't use clip regions because the design is clearly digital with almost perfect ground planes so it seemed that clip regions would only add unnecssary complexity to the EM Structure

Creating EM Document

1. Make sure that the two nets from the previous step are still selected.
2. Choose Layout > Copy to EM Structure.
• Use the default name.
• Select AXIEM as the Available Simulator.
• Push Create.
3. Choose OK in the Simplifiation Properties dialog.
4. Choose Draw > Create Ports from PCB Pins.
5. Note that ports are automatically generated at the component pin locations.
6. Choose OK in the Select EM Ports dialog.
7. Note that an EM Structure is created with just the selected nets and not other shapes because an EM Clip Region was not defined.
8. It only took a few clicks and a short amount of time to get to this point!
9. The EM Structure is now ready for manual refinement and simulation.