What programs to use for designing microwave filters with cavities?

Dear Forum,

The compnay i work for, it's now expand and need to design microwave filters with cavitys. They asked me to make a market search. I have not found any program which calculate the cavities. Also we need a packet to simulate if that is possible before we order it. We tried the concerto which is very easy to work with and has easy scripting but i am not sure that is the proper for the work we like to do. So could you please give me your opinion which set of programs we may use for that?
Thanks in advance for your time.

Re: Opinion need it

Hi
it's better that you use two software:
1. IE3d because it has cavity back simulation
2. microwave office because it has cavity in default

or you can HFSS or CST that we can model any shape cavity

Re: Opinion need it

And for initial design any suggestions?

Re: Opinion need it

hi
I think it's better that you start with CST

Re: Opinion need it

What type of filters are you looking at? Could you give a little more information about the size and shape of the cavities you would like to simulate?

Re: Opinion need it

Mostly combline and interdigital filters

Re: Opinion need it

hi
itis better to use HFSS for your designs.

Re: Opinion need it

You didn't say what kind of topology is used for your filters.

Here are my opinions, for what they are worth:

If you are looking at 3D cavity resonator filters, or waveguide cavity filters with tap resonators, inductive posts, irises, etc., with very high Q (very narrowband), then I would recommend you consider a finite-element frequency domain 3D EM software, like HFSS, Concerto, the CST FEM/freq domain tool, or other finite-element approach.

If you are looking at a wideband 3D (non planar) filter design, then I would recommend a time domain 3D software, like CST time domain solver, REMCOM, IMST or other FDTD or FIT approach software. The time domain codes seem to be more efficient when you have a wideband simulation.

If you are designing planar filters inside of a cavity, then I would suggest that you consider a shielded planar Method of Moments simulator, like Sonnet or AWR EMSight. These tools automatically assume a cavity around your filter. Sonnet even lets you put internal ports very close together inside your filter so you can tune extra coupled line sections or open/short stubs in a fast circuit theory simulator (like AWR or ADS) outside of the slower EM simulation loop.

Unshielded Method of Moments tools (like Agilent Momentum or IE3D) are better for antennas because they assume there are no shielding walls. They can do filter simulations without cavities, but their cavity simulation effects are more of an approximation, I think. For cavities with close spacing to the filter, the simulations must be very accurate because they have a fairly strong effect on the passband edges of the filter.

--Max

Opinion need it

HFSS works fine for cavity filters.

Re: Opinion need it

I liked Max's assessment of several software choices.

The way I see this is that there are several fundamental choices: Are you after analysis of synthesis software? Most of the software tools are really good at analysis and poor at synthesis.

another rule is : Good, fast, cheap. Pick only two.

Code that is not particular user friendly is often really useful while easy to use software has limited scope.



All that being said I would seriously consider HFSS (analysis orientation, good, not overly fast, not cheap, somewhat unfriendly but really flexible).