problem with designing filter

[boy]

Hairpin filter

DEar freind, I have a problem when I try to design filter. I use @DS to design a hairfin filter 5.66 GHz 200 MHz bandwidth. in @DS design guide, the result is look good but when i export the structure to MW studio 4.0 to do full wave analysis, the center frequency was shift. Any sugestion? tahnk you

 

[Sinuous]

Are you sure the dimensions were the same in both as well as the dielectrics and metal walls? In @DS these are not always obvious.

 

[eirp]

Re: Hairpin filter

DEar freind, I have a problem when I try to design filter. I use @DS to design a hairfin filter 5.66 GHz 200 MHz bandwidth. in @DS design guide, the result is look good but when i export the structure to MW studio 4.0 to do full wave analysis, the center frequency was shift. Any sugestion? tahnk you

Pay attention on mesh in MWS. In some cases (I think this is the one) it needs to be carefully refined. Try to run adaptive meshing wizard or play with mesh settings (lines per wavelength ~30, mesh line ratio limit ~50, refinement along pec boundary ~3 or 4).
Maybe it can help..

Best regards,
Eirp

 

[Sinuous]

EIRP:

I could not agree with you more. I am glad you brought up that point. The meshing in MWS is VERY important. I cannot tell you how many times I had incorrect simulations because the mesh was not correct. The real gocha is that the results can be WAY OFF.

Be sure to run the adaptive mesh for the first solve at least. After the first solve, you can usually just retain the mesh settings.

 

[boy]

I think the dimension is ok since @DS can export directly to MWS. I will try to redefine the mesh. Thank you very much.

 

[loucy]

Have you analyzed it with ADS's Momentum?

I would not expect MWS to give exactly the same result with other MoM or FDTD code even if the geometry is modeled exactly. How much shift are we talking about?

 

[boy]

I have tried momentum, but it is not good the result does not look like filter anymore. In MWS, it is sbout 200 MHz below the desire frequency.
I will try Adative Meshing tyoday to see how it is.