[SOLVED] SMA connector modes (HFSS wave port)

Hello everyone.
If I want to simulate a SMA connected source to a microstrip fed patch, should I use lumped ports or wave ports?

I am having this confusion as when I am using wave ports using sizing guidelines provided in the manual, a message is coming where it is showing that the port supports an extra propagating mode. But when I am adding more modes in the port definition and visualizing the port field display, I think the extra mode isn't correct. So my question is does SMA connectors only allow the quasi TEM mode in a microstrip or shall I allow another mode as the cutoff frequency(again obtained by plotting imaginary value of gamma in HFSS) is coming lesser than my operating region.

Or using lumped ports with integration line from feed line to ground plane will give the more realistic results?

srijan.rio said:

Hello everyone.
a message is coming where it is showing that the port supports an extra propagating mode. But when I am adding more modes in the port definition and visualizing the port field display, I think the extra mode isn't correct.

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For whatever reason the new version of HFSS always complains about more modes. Obviously, there's only one TEM mode. I would just ignore the warning and go with the manual.

okay so you use wave ports itself while simulating, defining only /one mode. Am I correct ? Also can you help me in another regard. While designing resonators, do the box sizing guideline of lamda/4 be followed as the structure is not radiating ?

srijan.rio said:

okay so you use wave ports itself while simulating, defining only /one mode. Am I correct ?

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Yes.

srijan.rio said:

While designing resonators, do the box sizing guideline of lamda/4 be followed as the structure is not radiating ?

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It's still a good idea. There may be near-field coupling effects with the radiation boundary otherwise.

PlanarMetamaterials said:

It's still a good idea. There may be near-field coupling effects with the radiation boundary otherwise.

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Pardon me if I am asking a trivial question, but isn't it applicable when I am specifying my boundary box as radiation boundary? I have verified some resonator structures but without specifying the boundary as radiation and results did concur. Can you please tell me whether its correct way of simulating or not. Also if I don't assign the rad boundary, near field coupling shouldn't occur right ?

Thank you very much for your time and responses

It depends if the automatic domain boundary setup is turned on or not. If there's actually no radiation boundary, then by default the outer edges of the simulation domain will be PECs.