need help on HFSS9.0 solution frequency selection/sweep type

Hi, everyone:
I am simulating a CPW with HFSS v9.0 from 1-40GHz, I found the simulation result changes with solution frequency and sweep type. More specifically I simulate it at 20GHz, 25GHz, 30GHz. The results of 20GHz and 25GHz are similar, but at 30GHz is different. Also the fast sweeping results are different from interpolating ones.
I am frustrated on which simulation result I should trust. Any advice is helpful.

Thanks in advance.

Anglerep

hi...
i can understand your pain using HFSS...
well , for starters, HFSS should never be used for such large band of frequencies unless you are using big steps....
Another pointer is your mesh size larger then the highest freqeuncy you are trying to cover(f mesh> f largest)?
The reason you will get different value is because at some frequency the mesh might not cover some edges which will result in weird results...(typically cpw will be sensitive at the edges).So again my advices is make more denser mesh to obtain good results..

Finally, use discrete sweep...to me it yield the best result...fast is an approximation and interpolation comes close to discrete but may differ at times