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RF Module - Waveguides with arbitrary cross sections: numeric ports setting
Posted 13 nov. 2011, 08:59 UTC−5 RF & Microwave Engineering, Wave Optics Version 4.2 1 Reply
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Hi to everyone,
I'm new to Comsol Multiphysics, and I'm trying to simulate some waveguides with arbitrary cross-sections. My problem is that it isn't clear to me the meaning of the numeric settings port, in particular:
"Desired number of modes"
"Search for modes around"
I didn't find a clear answer in the Comsol help or in the model examples. Could someone tell me the physical meaning of this two settings?
Thanks!
Bye
I'm new to Comsol Multiphysics, and I'm trying to simulate some waveguides with arbitrary cross-sections. My problem is that it isn't clear to me the meaning of the numeric settings port, in particular:
"Desired number of modes"
"Search for modes around"
I didn't find a clear answer in the Comsol help or in the model examples. Could someone tell me the physical meaning of this two settings?
Thanks!
Bye
1 Reply Last Post 18 nov. 2011, 16:31 UTC−5
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Posted:
1 decade ago
"Desired number of modes" is just the number of eignmodes to solve for. For example, if you were only interested in the fundamental mode or you know you had a single-mode waveguide, then you would set this parameter to 1.
"Search for modes around" is like an initial guess. If you're working with effective mode indices, then COMSOL will begin it's search around/below the refractive index you enter here. For example, if you're modeling a silica fiber with an air cladding, then I'd enter 1.4. I think there is a choice with what eigenvalue you can enter here -- mode index, propagation constant, etc. Just make sure that you enter in the right number for whatever eigenvalue you choose!
"Search for modes around" is like an initial guess. If you're working with effective mode indices, then COMSOL will begin it's search around/below the refractive index you enter here. For example, if you're modeling a silica fiber with an air cladding, then I'd enter 1.4. I think there is a choice with what eigenvalue you can enter here -- mode index, propagation constant, etc. Just make sure that you enter in the right number for whatever eigenvalue you choose!