How to simulate 2.45 GHz microwave which consists of multiple modes?

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Hello. I'm simulating microwave heating equipment with COMSOL microwave heating module.

I would like to simulate chamber with 2.45 GHz magnetron connected to rectangular waveguide (7cm x 4 cm)

In COMSOL, I have to set propagation mode such as TE10, TE20 etc. but in real, I don't know the exact propagation mode and I guess multiple modes would exist due to the geometry of the rectangular waveguide.

Is this situation impossible to simulate? Any advice realted to COMSOL or waveguide physics would be helpful. Thank you so much.


3 Replies Last Post Jul 17, 2024, 10:37 a.m. EDT
Robert Koslover Certified Consultant

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Posted: 4 months ago Jul 16, 2024, 9:59 p.m. EDT
  1. The cutoff frequency for TE10 mode (the fundamental mode) for an empty 7cm wide waveguide is 2.141 GHz. This will propagate 2.45 GHz. Other modes will have higher cutoff frequencies and that waveguide should not support those modes at 2.45 GHz over any significant length of the waveguide. FYI, your stated size of waveguide seems to be non-standard. Most designers use standard waveguide sizes, when practical. See, among others, the list at: https://www.everythingrf.com/tech-resources/waveguides-sizes . .
  2. Yes, you can model waveguide and microwave ovens. Comsol even provides examples of such models, since this is a popular topic. See https://www.comsol.com/model/microwave-oven-1424, among others.
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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
1. The cutoff frequency for TE10 mode (the fundamental mode) for an empty 7cm wide waveguide is 2.141 GHz. This will propagate 2.45 GHz. Other modes will have higher cutoff frequencies and that waveguide should not support those modes at 2.45 GHz over any significant length of the waveguide. FYI, your stated size of waveguide seems to be non-standard. Most designers use standard waveguide sizes, when practical. See, among others, the list at: https://www.everythingrf.com/tech-resources/waveguides-sizes . . 2. Yes, you can model waveguide and microwave ovens. Comsol even provides examples of such models, since this is a popular topic. See https://www.comsol.com/model/microwave-oven-1424, among others.

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Posted: 4 months ago Jul 17, 2024, 1:03 a.m. EDT
Updated: 4 months ago Jul 17, 2024, 1:03 a.m. EDT

Your answer helped me a lot. I really appreciate it. May I ask you one more question?

I found that my waveguide was not actually a waveguide, but just a launcher. It means that I have to simulate 2.45 GHz microwave penetrating hallow rectangular object without guiding.

I want to know whether direct microwave heating without guiding and propagation mode can be simulated.

I already made my model through microwave heating module, but I guess microwave heating module only supports waveguiding situation.

Your answer helped me a lot. I really appreciate it. May I ask you one more question? I found that my waveguide was not actually a waveguide, but just a launcher. It means that I have to simulate 2.45 GHz microwave penetrating hallow rectangular object without guiding. **I want to know whether direct microwave heating without guiding and propagation mode can be simulated.** I already made my model through microwave heating module, but I guess microwave heating module only supports waveguiding situation.

Robert Koslover Certified Consultant

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Posted: 4 months ago Jul 17, 2024, 10:37 a.m. EDT

I don't understand the geometry you are describing. Can you post a picture? If by "launcher," you are referring to an antenna, then yes, Comsol Multiphysics can be used to simulate that. There are a variety of antenna modeling examples available. See, for example, those at: https://www.comsol.com/models?q=antenna

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
I don't understand the geometry you are describing. Can you post a picture? If by "launcher," you are referring to an antenna, then yes, Comsol Multiphysics can be used to simulate that. There are a variety of antenna modeling examples available. See, for example, those at: https://www.comsol.com/models?q=antenna

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