I'm designing a board that should contain an antenna I found in an application note. I'm using Eagle and I tried to create a library part for the antenna. However, since the antenna is basically a fancy-shaped short circuit, Eagle tends to report DRC error for it.
Is there a way to draw a PCB antenna in Eagle in such a way, that the DRC errors wouldn't show up?
No, there is not. Well, not for an antenna- You can make a junction with a soldermask opening that will create a short (if you use a stencil cut from the output of the CAM tools), but there's no way to join two different nets on a copper layer in the PCB editor.
Just keep doing what you're doing; it will produce a DRC error but that's OK.
As I wrote at How do I facilitate keeping multiple grounds, (i.e. AGND, DGND, etc…) separated in the layout when using Eagle?, you can move on by select one of the errors to enable the "Processed" and "Approve" buttons ("Approve" is the only one I use on a regular basis) and choosing "Approve" to move the error from the errors list to the approved list:
and will stay there on subsequent runs of the DRC. Note that this only moves this specific error with this specific pair of nets at this specific location. Closing this window and running the DRC again produces the notification "DRC: 1 approved errors"
and no "DRC Errors" dialog. When you don't get a new DRC errors dialog, you're done!
As of Eagle version 5 at least, no it is not possible. You can make a library part with arbitrary fancy copper shapes, but you will get DRC errors. You only have to go thru the DRC errors once and approve them, then they won't pop up again unless you touch that part.
I hear that there will be a way someday to define arbitrary pad shapes in a library part and have DRC not complain. That may already be available in the new version 6, but I'm not going near that for a while so I wouldn't know. Let all the people who don't have better things to do find the bugs in the major new version of Eagle.
