Is it possible to define a port that is DC only in HFSS?

Hello everyone,

While I have been using HFSS 11 for about two semesters, I am still relatively new to the software. I want to add a DC source to a biasing network for a varactor. I plan to model the varactor just as a lumped element capacitor. The purpose of the DC source is to see the impact within HFSS of the biasing network on an antenna array performance. The biasing network is a quarter-wavelength transformer.

So, is it possible to define a port that is DC only in HFSS?

Thanks in advance,

Paul

Hi Paul, u can embed ur HFSS design into Ansoft Designer, then put ur DC sourcesand varactor in Designer. U gotta define lumped ports in ur HFSS design in order to make the connection with the lumped element (varicap) in Designer. Import form Designer itself the HFSS design by creating an HFSS dynamic link. Designer will see an n-port connected to the DCs and nonlinear varactor element. It is possible to enforce the excitation from Designer by clicking 'push up excitation'.
In such a way there's no need of approximating the varicap with a simple capacitor, but u can use the non linear model in Designer or Nexxim. Furthermore, u will be able to check the imput impedance behavior of th whole system. A detailed description of dynamic links is reported in the Designer Help.

Hope this helps.

Bye.

I.

Thanks for the information, Ivan, but unfortunately I do not have Ansoft Designer. Is there a way to do this directly though HFSS 11?

HFSS is only for full-wave eletromagnetic simulation. You can do your mixed simulation for your problem as follows:

(1) obtain the s-parameter for your array by HFSS full-wave eletromagnetic simulation.

(2) import s-parameter into circuit simulator (ADS, Designer, microwave office, etc), add the lumped elements and do the simulation.

I hope this can help you.

You can add elements (3D) to your model that resemble the elements of your bias network, much as you might add vias, pads, etc. to the physical model. This can enhance the fidelity of the simulation.

I agree with the earlier comment, using Designer is really the way to incorporate active components in a HFSS simulation.