HFSS Solution frequency

[venu.gongal]

Hi

I am designing a cavity filter with fo @1600MHz and 50MHz BW in HFSS. So, I setup a solution frequency @1600MHz and the results are slightly different (offset by 50MHz) from what is given in the IEEE paper ("True Inline Cross Coupled cavity Filters ").

I am using fast frequency sweep (1GHz-2GHz).

I thought meshing frequency is good enough so increased the meshing frequency(solution freq) from 1.6GHz to higher freq(10GHz). The r

I see completely different results. I dont understand what the problem might be..


Please help me out..


Thanks
Venu

---------- Post added 19-12-11 at 00:07 ---------- Previous post was 18-12-11 at 22:48 ----------

Meshing frquency was not good enough so increased it to see that my results are worse than before.

Should I use discrete frequency sweep and use frequency dependent solution setup??

Kindly help

Thanks
Venu

 

[kuandonggao]

Yea,you can use the discret sweep

 

[amihomo]

First of all, select the appropriate maximum number of passes and delta S.
For most designs the choice of 15 and 0.02 for the aforementioned parameters is enough.

For resonant structures, as is your case, the fast sweep works well; but you should choose the setup frequency equal to the mid-band frequency.
If you choose to use the discrete sweep you should set the design frequency equal to the maximum frequency of operation.

 

[venu.gongal]

Hi

Thanks for your replies.

I will write down what I have done.

I used fast sweep with a solution frequency @ 1.6GHz (in pass band) , convergence achieved (after 11 passes) with lambda refinement 0.33 (default)-- I get expected results perfectly,

Now, I increased the solution frequency to 2GHz (Out of pass band) , convergence achieved (after 21 passes) -- completely erroneous results.

I increased by solution frequency to 10GHz (Out of pass band) convergence achieved (after 14 passes)--- I get accurate results.
--------------------------------------------------------------------------------------------------------------------------------------------

May I know the reason for this discrepencies..

Also the dependence of lambda refinement on the solution.

Thanks
Venu

 

[ferdows]

hi
pls send your file i will check it for you

 

[venu.gongal]

Hi Ferdows

Attached is the file

Best*.* ---- solution Freq @ 1.57GHz

Temp*.* --- Solution Freq @ 10GHz

If I change the Solution freq between 1.57 to 10GHz--- I find weird Results...


Thanks
Venu