Chris- To a high frequency signal, there is no difference between "GND" and "Vcc". The problem is that there must be a discontinuity at the location where the signal changes return path from only the PCB GND plane (or SMA ground) to also including Vcc plane as well. For example, if an SMA cable connects to a PCB. The return path of the signal inside the cable is external conductor of the cable, which is likely connected to the GND plane on the PCB. In order for the return current to travel on Vcc, it must travel either through the impedance of either a bypass capacitor or the impedance between planes (whichever way is lowest impedance). This will cause an impedance discontinuity. The problem is that this impedance discontinuity is very application specific. Each design will be different at this transition. As with a lot of SI issues, it's very difficult to generalize. I recommend the best way to understand this issue is to use a field solver. Regards, Ryan Satrom Everett Charles Technologies --- In si-list@xxxxxxxxxxxxxxx, "Christopher Rodenberg" <c.k.rodenberg@...> wrote: > > Hi folks, not sure if dual-ref is the right term, but I'm looking for > info on stripline with one ground plane and the other at Vcc. I'm > trying to gauge the effects of this configuration versus normal > "ground sandwiched" line. Any tips/sources? > > Chris > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@... with 'unsubscribe' in the Subject field > > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@... with 'help' in the Subject field > > List FAQ wiki page is located at: > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > > List technical documents are available at: > http://www.si-list.org > > List archives are viewable at: > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu