Importing Gerber Files in

ADS 2008U2

By

Rea Schmid

Abstract: This document steps you through importing Gerber Files into ADS layout editing tool. Once the Gerber layout is imported discrete components are added and full 3-D simulation with component’s S-parameter models can carried out. This is more accurate than non-magnetic or Smith Charts to calculate baluns, microstrip lines, or filters.

Note: Simulations once the models are validated is a true representation compared to lab measurements. It is very hard to not cause some additional parasitic components to be added when connecting lab equipment regardless of normalization and calibration.

  1. Create a Project by selecting New Project found under the File tab at the top of the window.

  1. Using a window browser make a folder within the project and name it Gerber_Files. When making names in ADS it requires no spaces between words so make sure no spaces exist in folder names or file names.

  1. Copy your Gerber Files to this location.
  2. Open a new layout editor window.

  1. Under tab at the top “File” select “Import”

  1. Under “File type” select ADS 2006A Gerber Viewer, then depress OK
  2. A new window appears but often you must select view all to see the Gerber Files and their extensions.

  1. Select all Gerber File extensions which you want to import. Generally you only need the top and bottom layer if a 2-layer board is being imported. All other files pertain to mechanical or solder paste, etc. This is a 2-layer board so select .GBL and .GTL
  2. Use CTRL and place cursor over the desired file name.

  1. The Gerber Viewer displays the layers you’ve selected.

Both layers are loaded and now can be view one at a time by select which layer under the layer button to display.

  1. Translating to ADS layout editor - select tab “Tools” at the top of window folder. Then select “Gerber Union” This opens a new window

You can fine tune the various settings but for most translation the defaults work fine. Check the Help button for explanation of each setting. Altering the settings can speed up simulations but one need to understand the rules for changing. Note the Output File Name at the bottom of the window. This is the file that will be imported into ADS layout editor. Depress OK and the translation is completed with a window saying the translation was completed without errors.

  1. Close the Gerber View by selecting the x. From the File tab in the layout editor select “Import”. Then select in the File type pull down “EGS Archive Format”. Depress the Browse and select the “filename” with path, no spaces allowed in the name. As you can see this has a space so I use browser to rename the file and add an underscore for the space. The layers file name is loaded automatically. Occasionally you must create this file name in your project directory, “Layout.lay”, if error appears.
  1. A message window appears acknowledging the transfer was completed OK.
  1. You can edit the layers, turn them off and on or change colors by open the layer editor. The most recent layers are always at the bottom. The un-used layers can be deleted by placing the cursor on them and depressing cut.
  1. Turn off all layers but the top and the display will show the top layer.

At this point I usually edit out the bottom template so only the layout remains.

  1. After you edit the layout you probably need to size the drawing so that your selections and scale is easier to see.
  1. Sizing the import. Open the Preference found under the Options Tab in the top window. There are several selections to be made starting with the layout units.

These settings are for text, snapping, probe size, layout scale etc. Make sure the settings are what you desire before any edits are done or you will need to start from the beginning.

  1. Select all objects on the layer you are viewing and from the “Edit” tab at top of window, select “Components” and “Flatten”. Then re-select the objects {should be high lighted} and from “Edit” tab select the “Merge” then “Union”. After Union check to make sure objects physically connected are highlighted when selected. See below:

If you don’t see the various traces and grounds highlighted you need to repeat this step until everything is merged properly.

  1. From the component menu select the discrete components from the vendor series. If you don’t have the vendors models loaded you must go to the manufacture web site and find the ADS libraries to load their models. Below shows some of the components added.
  1. To finish up you add the probes on the pins and follow the setup in momentum to run a simulation with board.
  1. If you choose to build up a schematic and simulate you will fine this answer slightly different because it doesn’t include the fields generated by the traces. But this is a constant error so the measured points are accurate to about 5 to 8%. I use a Gerber Viewer to obtain the trace lengths and widths then place the component models in between each trace. This is shown below: