Coaxial cavity resonator

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I am trying to model a coaxial RF resonator cavity. It consists of hollow outer and inner cylindrical conductors (copper) and are shorted on the two ends by a copper caps. I added impedence boundary conditions to include the losses. I have added Eigenfrequency study. The issue is, when I "compute", I am getting this error: Undefined variable.

  • Variable: comp1.emw.Qfactor

  • Global scope

Failed to evaluate expression.

  • Expression: comp1.emw.Qfactor

  • Feature: Eigenfrequencies (emw)

Can you please explain me what am I missing? Also, apart from this error, how should I proceed with this modeling?


1 Reply Last Post 13 mar 2026, 10:50 GMT-4
Robert Koslover Certified Consultant

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Posted: 2 hours ago 13 mar 2026, 10:50 GMT-4
Updated: 2 hours ago 13 mar 2026, 10:52 GMT-4

I can imagine a number of possibilities, most of which are very easy to fix. If you post your model to the forum, people will be able to examine it and will be better able to help you.

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
I can imagine a number of possibilities, most of which are very easy to fix. If you post your model to the forum, people will be able to examine it and will be better able to help you.

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