monopole hfss

Hi,
I want to simulate a wire antenna like a lambda/4 monopole in HFSS.
I've defined a cylinder filled with copper and a ground plane.
But how I define the excitation for the antenna?What I have to use and how?
Thanks.

You can use a lumped gap port on a 2D rectangle between the wire and the groundplane. Or you can use a wave port by assigning it to the outline of a circle on the groundplane (this treats the monopole like the inner pin of a coaxial line).

The impedance of the lumped port is assigned by the user, while the impedance of the wave port is found by the 2D port solver.

Hi ifelix,

I normally use 'driven terminal' analysis and waveports to simulate monopoles or dipoles with coax-feeds.

Hope this helps,
David

what difference between lumped port and wave port?

look at the example it will help you

pl

This is the example on HFSS document, in this case, they used waveport (not lumped port). Have you ever tested using lumped port?

I've created a coaxial feed with internal conductor connected to the monopole and calculated to have 50 Ohm as carachteristic impedance.
Then I've tested waveport and lumped port at the coax entry and I've obtained the same results.
I've looked at S11 and Zin and they are very similar. Also the Zin=36 Ohm about and this agrees with the theoretical value of lambda/4 monopole...
Regards.

I learn HFSS v5 since two days ago, to model finite groundplane monopole antenna. I get difficulties in defining port.
Some members of this forum have been successful in modeling monopole antenna. Please send you monopole's hfss file to me. I want to learn from you.
Thank you very much.

Dear plasma:

Thanks for the document you support. It really help me a lot. Thanks.

does this also apply to hfss v9 and above?

Hey I m designing lamda/4 monopole in HFSS. what length and diameter should I take? Plz reply urgently.

for lambda/4 monopole the radius of cylinder can be taken as lambda/200