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RF Mode Analysis Normalization Convention

Posted Nov 18, 2011, 4:34 p.m. EST RF & Microwave Engineering, Results & Visualization Version 4.0, Version 4.0a, Version 4.1, Version 4.2, Version 4.2a, Version 4.3 3 Replies

Ryan
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Hi all,

This question is in regards to: RF Module > Electromagnetic Waves > Mode Analysis

Does anybody know the normalization convention that is used in the solutions? For example, part of the solution are surface plots of the electric field. The shape of the field distribution is dictated by the specific eigenvalue problem; however, the actual values given by COMSOL are quite arbitrary (i.e. you can always include a multiplicative constant with impunity). How then, does COMSOL determine what numbers to give in the solution for field components, power, etc.?

My first thought was that the integrated power flow would be normalized to 1 W, but, as far as I can tell, this isn't the case. Other obvious integrals over E^2 or H^2 don't seem to indicate any type of obvious normalization either.
3 Replies Last Post Nov 30, 2012, 12:51 p.m. EST
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Ryan
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Posted: 1 decade ago Feb 8, 2012, 6:49 p.m. EST
bump.
bump.
Ali Anderson
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Posted: 1 decade ago Nov 30, 2012, 12:31 p.m. EST
Anybody knows the answer to this ?
Anybody knows the answer to this ?
Ryan
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Posted: 1 decade ago Nov 30, 2012, 12:51 p.m. EST
Here's the answer I ended up getting from support:



" COMSOL normalizes the solution with respect to the numerical matrices based
on the assembled finite element system matrix.

There is no particular physical basis to this.

I agree that this would be useful to add but we do not have this
functionality as of now.

You could normalize a mode manually, and making sure that the total energy
is one. Energy density is available as a derived quantity. "



Not exactly the rigor I was hoping for, but I suppose that if it works, it works.
Here's the answer I ended up getting from support: " COMSOL normalizes the solution with respect to the numerical matrices based on the assembled finite element system matrix. There is no particular physical basis to this. I agree that this would be useful to add but we do not have this functionality as of now. You could normalize a mode manually, and making sure that the total energy is one. Energy density is available as a derived quantity. " Not exactly the rigor I was hoping for, but I suppose that if it works, it works.

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