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Oblique incidence and floquet condition problem

Posted 15.01.2013, 22:16 GMT-5 RF & Microwave Engineering, Results & Visualization Version 4.3 2 Replies

Jungho Kim
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In the RF module, I found that there are 2 problems.

First,
When the thickness of the layer which uses scattering boundary condition gets thin (below ~200nm), the direction of power flow [sqrt(emw.Poavx^2+emw.Poavy^2+emw.Poavz^2)] doesn't go 90 degrees even if I set the incident angle as 90 degrees.

Second,
The power flow distribution reaches below some part of port condition area even if I set the incident angle as 90 degrees.

I also tested it in the plasmonic wire grating of model library which uses port condition instead of scattering boundary condition. However same problems occurred.

I attached figures of my question.

please help me.
2 Replies Last Post 16.01.2013, 12:59 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 16.01.2013, 00:57 GMT-5
Hi

but if you go too thin, the skin effect will make the material more and more "transparent", and the amount of energy passing will influence the E field hence act on the angle, no ?
But I might have missed something

--
Good luck
Ivar
Hi but if you go too thin, the skin effect will make the material more and more "transparent", and the amount of energy passing will influence the E field hence act on the angle, no ? But I might have missed something -- Good luck Ivar
Alexander Kuznetsov
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Posted: 1 decade ago 16.01.2013, 12:59 GMT-5
First of all, you should use 1 set of periodic BC, not 3 identical. Helps avoiding mistakes :)
Second, use ports instead of scattering BC.
Third, floquets are implemented correctly in COMSOL. I've tested the results vs. independent EM solvers.
Finally, regarding oblique angles: your model is not setup correctly to launch waves at 90 degrees. So what you are seeing is some kind of artifact.
First of all, you should use 1 set of periodic BC, not 3 identical. Helps avoiding mistakes :) Second, use ports instead of scattering BC. Third, floquets are implemented correctly in COMSOL. I've tested the results vs. independent EM solvers. Finally, regarding oblique angles: your model is not setup correctly to launch waves at 90 degrees. So what you are seeing is some kind of artifact.

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