I can't suggest much that hasn't been already stated. A good reference book "Printed Circuit board design techniques for EMC compliance" (ISBN0-7803-5376-5) it has interesting advice about different layre stackups and the effects on inductance and decoupling (now 9 years old but still in print) It doesn't suggest removing the Vcc layres for RF design.
I think that I would still use Vcc planes and decouple heavily (nobody ever got the sack for adding more decoupling ;-) ), but perhaps it is worth questioning this... At 3GHz can you assume that your Vcc and GND are shorted any more? Probably not, but I suppose that depends on your power topology and the inductance of the Vcc line. Everyone seems to agree that the amount of capacitance that comes from the planes is minimal and that noise can be distributed by the power planes. I can see that your consultant didn't voice himself in the most politically sensitive manner. I've never seen it advised that Vcc planes be completely removed, but, since they don't really add much decoupling capacitance, you might imagine times when routing thick tracks as differential pairs with the ground plane on signal layres would make the design less likely to have ground loops or mistakenly violate moating. Perhaps you'd be best to ask him why he see's Vcc planes as categorically wrong? I'd be interested to hear back what he says ;-) _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
