Finally , i lost the hope to solve my problem (trying to get the resonance of a magnetron cavity) by using the HFSS and i need you suggestions to switch to another software package.
Some of my friends advised me to use the Zeland Fidelity, so what do you think ??
What kinds problem do you want to solve? Please let me know at: jian@zeland.com. I am from Zeland Software, Inc. (producer of IE3D and FIDELITY). Thanks!
I'm not sure that you want to use a time domain 3D tool for a problem like this. I think an eigenmode-based solver (like CST Microwave Studio eigenmode solver) is a better fit to this kind of problem. There might be others out there as well.
The problem with time domain EM tools for highly resonant structures is that they store energy for a really long time in the time domain...so you have to simulate them for a really long response window in order to get the proper Q for the structure response. For things like magnetron cavities, I think time domain solvers are probably the least efficient for getting the solution.
If the resonance is very sharp (which would be the case if you use a model with lossless metal), then a finite-element solver in the frequency domain could easily miss the resonance. You have to be careful to take many fine samples with a frequency domain solver if you want to find the resonances.