Simulation result of Microstrip line

Hi, I try to simulate the microstrip line.The simulation result is as attachment.
There is something wrong at low frequency.I have no idea how to get correct answer. May you give me advices? Thank you very much.

where is the simulation files? I cann't see them from here.

I think you have used a fast frequency sweep.
Use a discrete, seta up the solve freqeuncy above 40 GHz, solve again.

Look at the " HFSS 9.2 book" posted on EDA about 2 months ago,
there is an diff t-line example

Hope this helps

hi, could you please indicate that the material of your microstrip line?eg: FR4 or something else

Hi Jslee -- If you are using the volume meshing part of HFSS, switch to the planar solver (it meshes only the surface of the metal of your microstrip line). I would think that the HFSS planar solver should have no problem with a microstrip line, including using their interpolation, but I have no actual user information on it. If it turns out you get results like that using the HFSS planar solver, you should switch to another planar solver.

There are quite a few of them, I suggest SonnetLite (no time limit, free download at www.sonnetsoftware.com, I work for Sonnet). It will take about 5 minutes to install and register. Then, about one hour to read the tutorial (Help->Tutoiral), then about 5 minutes to capture, analyze, and display your results. The Sonnet interpolation (ABS, Adaptive Band Synthesis) is good for very wide bandwidth (1000X and more) and typically requires one half to one quarter the number of analysis points compared to all the others (we do something very different from everyone else).

Sonnet does not exhibit failure modes like what you posted. As for failure modes the Sonnet ABS does have, it does take a very long time if you have a lot of box resonances, the results are still accurate but we consider that a failure mode anyway (a few box resonances are OK). It also fails if you need to interpolate below the analysis noise floor (100 to 180 dB down). Both situations are rare but skilled engineers should be aware of the possible failure modes for whatever tools they are using.