Very bad results of HFSS for an X-band Waveguide Filter

EDAboard.com Forum Index -> RF, Microwave, Antennas and Optics -> Very bad results of HFSS for an X-band Waveguide Filter

Author

Message

Matthew_Dawson

Joined: 07 Jun 2009
Posts: 2

07 Jun 2009 5:53 x-band filters

We have analyzed, simulated and built an X-band waveguide filter. we performed a simple circuit analysis of the filter and an analysis using HFSS and later with CST microwave studio. The discrepancy between measured and circuit analysis results is small however simulation results show significant frequency. I have double checked everything yet this problem was not resolved. I'd be grateful to hear your suggestions. Here I attached simulation files and results.

Google
AdSense
Google Adsense

07 Jun 2009 5:53 Ads

Sorry, but you need login in to view this attachment

ansonjimli

Joined: 29 Apr 2006
Posts: 21

15 Jun 2009 3:20 mesh seeding,hfss

you should mesh more densely to get an accurate results. HFSS is good for this waveguide structure.

burton

Joined: 12 Dec 2003
Posts: 198
Helped: 9

16 Jun 2009 2:33 cst studio mesh

HFSS is better for high Q filter, but mesh seeding may be used, especially for the coupling section with evanscent waveguide.

Matthew_Dawson

Joined: 07 Jun 2009
Posts: 2

16 Jun 2009 7:14 microwave filter with waveguide hfss

Thank you for your replies.
The Q-factor of the filter is 20. There is 1.8% frequency shift in the response of the filter. this problem was not resolved even when I used very dense mesh. (1.5GB of RAM was used for an x-band filter)
I ran the simulation with CST microwave studio, as well and used very dense mesh. It took 6 hours to do the simulation. However, results of CST Microwave studio is similar to HFSS and exhibits a frequency shift of 1.8% which results in considerable error due to narrow band behavior of the filter.
I'd appreciate to hear your comments.
Matthew