How to find Resonance frequency of rectangualr cavity from FDTD data

[confi999]

Hello,
I have written 3D FDTD code with Mur ABC which gives correct results for time domain data.
Now I want to compute the resonance frequency of a rectangular cavity using this 3D FDTD code.
I don't know how I will do that.

Would someone please advise me the steps I need to follow now to calculate the rectangular cavity resonance frequency.
Any code or help on how the time domain data need to be processed is highly appreciated. Thank you.

 

[f95toli]

Maybe this is a silly suggestion, but could you just use a chirp pulse (or even white noise) as an input and then use an FFT on the output?

I can't think of a better method right now, of course you could just "scan" across frequencies and look at the amplitude of the output; but chirp+FFT should be faster, and I believe this is how it is usually done in e.g. SPICE simulations.