GBRUnion was developed to help designers clean and convert Gerber files to contour data. It does this by performing a union operation on draws, flashes and areas. Once a layer has been unionized there are no overlapping or touching boundaries. The resulting file can be output as Gerber, DXF, GDSII or EGS Archive.

Applications

At right is a snapshot of Gerber data for the top metal layer of a ball grid array. You cannot easily tell what Gerber commands (strokes and flashes) are used to create the image.

If we change the viewer to display only centerlines we can now see that the Gerber file consists of many overlapping strokes and flashes. If you were to convert this directly into DXF for import into a EM analysis tool, one would have quite a lot of cleanup to do before the data was ready for analysis.

By running this file through GBRUnion we see it has been reduced to simple and clean contours. This is how a field analysis tool would like to read the data so that it can be "meshed."

Several outputs are available depending on the tool you use: DXF (Ansoft/Maxwell), EGS ( for users of Agilent's ADS/Momentum) or GDSII (AWR). There is also a version of GBRUNion integrated into CST's Microwave Studio.

Importing Gerber into ADS - this note describes how to use GBRUnion to import Gerber data into Agilent's ADS/Momentum layout system.

Importing Gerber into Ansoft - this note describes how to use GBRUnion to convert Gerber data into DXF that can be imported into Ansoft's field analysis tools.