Why we need to set Et=0 in planar filter simulation in MWS?

[boy]

CST MWS questions

I have some questions in using MWS. why we need to set Et = 0 in planar filter simulation. I use the wizard which come with MWS, it set all boudary condtition to Et = 0 which mean PEC. I think only ground plane should be Et = 0 not for all boundaries. the rest should be open boudary. but when u set the rest to be open. It seems that the result is not correct. Any reason. I have tried to use Transient Solver and Eigenmode Solver. According to CST document, for high Q struture, I should use eigenmode solver. is that true??

 

[pewang]

if you don't use a housing for your filter,you can set boundery to open.

 

[boy]

is that the case? I set the boundary to open but eigenmode solver does not work. that why i am curious.

 

[eirp]

is that the case? I set the boundary to open but eigenmode solver does not work. that why i am curious.

Eigenmode solver must have well defined boundary conditions. Open resonator isn't this case.

 

[burton]

Re: CST MWS questions

Yes, you can simulate the planar structural filter by eigenmodel solver(modal analysis) in CST. But you should set the boundaries to PEC for eigenmodel solver, that is to say the structure you will simulate should be closed by PEC. If the structure is closed, you can add space by 1/4 wavelength to the boundaries and then set the boundaries to PEC.

 

[Element7k]

Re: CST MWS questions

Hi

In help>content>setting up simulation>which solver to use,
it defines that the eignemode solver can not be used with open boundaries, lossy materials, lumped elements or discrete ports

:idea: Element7k :idea:

 

[midnite]

Re: CST MWS questions

it is important the dimension of the ports too

midnite

 

[asjade3]

Re: CST MWS questions

unfortunately, MWS's eigenmode solver can't work with the open conditions, but HFSS can do.