Q3D issuse: why DC resistance is greater than AC resistance at 60Hz and 20kHz?

templortemplor Member Posts: 2

I'm working on extraction  of parasitic parameters of power module by Q3D.

For default, AC resistance&inductance is extracted at 1GHz. The results from this setting looks good, and AC resistance is much greater than DC resistance due to skin effect and proximity effect.

However, the results are wired when I change the solution frequency to 60Hz or 20kHz, the DC resistance is 10 times larger than AC.

Does anybody have the same issue, or give me some suggestion about it?




  • MayankMayank Member Posts: 6


    I am also working on Q3D and facing the same issue .

    Did you found some reason for that ?

  • rtkrtk Pune, IndiaForum Coordinator Posts: 165

    Hello @templor, @Mayank

    I would suggest going through the Q3D Extractor help document covering AC vs. DC Analysis. This has covered the interpretation of the AC and DC regions by Q3D extractor.

    So for your case at 60 Hz or 20 kHz, the skin depth might be greater than the actual conductor thickness and thus the AC resistance at this point cant be reliable. You should go for DC resistance.

    You might need to check what is the threshold frequency at which you can rely on both AC and DC resistance for your model according to the expressions in the help document.

    Hope this addressed your concern.


Sign In or Register to comment.