SDD_ADS_capacitor membrane vibrating

Hello,
I have a problem in modelling a non-linear capacitor. Lets say that the capacitance is changing due to vibrations and which is continously happening. Suppose I am interested only at this mechanical resonance frequency, How can I model it in ADS?

So the crux of the problem is this,

1. Capacitance continuosuly changing due to vibrations.
2.Only interested to see this non-linear effect at a certain frequency since it will mix with another frequency. So, I need to do a harmonic balance simulations.
3. But first I want to simulate this mechanical capacitance

Would appreciate if someone has an idea on how i can model it.

thanks

Why not call it a varactor diode and put a variable sinewave across it?
Frank

Hi Chuckey!
yea, i have been trying to simulate the same. So, I have apply a time-varying DC voltage to this varactor. I was thinking of using an ideal capacitor whose capacitance is a function of voltage. But how can I feed this voltage? Using a simple sine wave source? I need to be able to simulate a 0.03fF delta C change at a certain frequency and output a harmonic balance simulation where i can see this frequency mixing with my main sigal source. can you tell me how I can do it?

thanks!