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Meshing Conductors that are Thinner than the Skin Depth HFSS

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etothe456t

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I'm simulating a conductive ink trace on a dielectric substrate. The microstrip is long and it's thickness is smaller than the skin depth.

IE: Length = 500mm, Width = 0.5mm, Thickness = 10um; Skin Depth = 100um, f = 150MHz

I know typically when simulating conductors that are larger than the skin depth in HFSS, solve-inside is not set and HFSS automatically calculates losses in the conductor.

I think I should now set solve-inside to the object, but does this alone set an adequate mesh? If not, how should I set mesh operations to adequately mesh this structure in this situation?

Also, what kind of mesh operations would you suggest in regards to the dielectric which is also very thin (25um) and very long (500mm)?

Thank You...
 

sweetjimmy

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1. When using solve inside, I would recommend adding a mesh seeding operation to "kick-start" the mesh in the conductor. Select the trace object, HFSS > Mesh Operations > Assign > Inside Selection > Length Based.
2. Uncheck "Restrict length of elements" and Check "Restrict Number of elements," and enter something like 5000 to add elements inside the trace object.

If you are solving just the straight section of transmission line, you might want to just solve 5mm in length, and then use a negative de-embedding on the waveports to extract out S-parameters for 500mm. This has worked well, and I have extracted accurate S-parameters for a 30" section of line by only solving 50 mils.
 

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