hfss assign voltage

Hi, everybody, I'm doing some simulation about striplines in HFSS. I have some doubts, there are 2 ground planes in stripline ,how should i define them as same voltage?And how to set up the excitation? thank u~

hi shannon18,
first of all i didn't get why you want to assign voltage to the ground plane, but i can answer how can you assign excitation, if you r using the ground plane as a three dimensional object just you need to assign its material property to some metal like copper, or else if your ground planes are two dimensional 'select the plane of the object you want to assign as ground plane and assign excitation as "some "perfect E plane" like thing would be there in HFSS i forgot the exact word so select whatever there in the excitations llist with the letter E"'

There is no concept of ground in HFSS. In other
words, the excitation is between two conductors
and no one is referenced to anything. They are
somehow considered differential.
So in striplines both planes must be connected
by the definition of the port or by connecting using
a via.

Your question is straight forward. The answer is not. I recommend you talk with one of Ansoft's Application Engineers. You might want to look into lumped, wave and terminal ports, "caps", and the various forms that the impedance calculations (search in on line help) can take. They also have a user's guide (for 10.0) that is helpful. (Version 11's guide is not out yet.)

Hi friends
I have 1 doubt.
In strip line do we have to provide excitation as shown in above figure
If not then how to provide. can anyone upload any image.
thank you
ABhishekabs

My first reaction to your fugure is that the port is too small. I would as a minimum want to cover the dielectric. The excitation should be fron one of the ground planes to the center not ground to ground as indicated. As I said earlier becareful of node ve. terminal ports. You might also consider if you want "background" or vacuum around your stripline.

Thanks azulykit
You solved my confusion about excitation of port.

Lumped Port defined between the strip & Gnd plane( either or the nearest Gnd in assymetric Stripline) showed more practical results. Waveport showed lower transmission loss.

Added after 10 minutes:

@ Azulykit

No appreciable difference in either exitation ( Gnd-toGnd OR Strip-to-Gnd). I think, Lumped port is more appropriate and gives more practical result than waveport.