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Split ring resonator eigenfrequency help in RF module

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Please find attached my model of a U-shapped split ring resonator in COMSOL's RF module. I am somewhat of a beginner with COMSOL. The idea is to find the eigenfrequencies of the resonator, so by applying an electromagnetic field on the resonator I want to see at what frequencies of the incident wave is the amplitude of the resonator the highest.

The resonator dimensions are in nano-meters and is supposed to be made out of copper. Also I have surrounded the resonator with a large cube of air. I have imposed the PEC condition on the front and back faces of the cube and also have an incoming electric field from the front face. On the left and right hand faces of the cube I have imposed the PMC condition with a magnetic field entering the cube from one of these faces. The reason for the magnetic and electric fields is to provide an incident electromagnetic wave on the resonator (is this method correct). On the top and bottom face of the cube I tried to impose the scattering boundry condition but when I compute i get an error saying that something is missing in the stress matrix and I am unable to fix this. But if I leave the top and bottom face without any boundry condition I am able to compute. However I get purely complex eigenfrequencies with negative power for eg. -9.5e-5i, 5.6e-4i etc. This in my view is not correct.

Can you please help me with the following:

1. General comments on how to go about making such a simple simulation.
2. I have tried many tutorials and solved comsol examples but am unable to understand how to impose proper boundry conditions (which ones would be the proper ones in this case).
3. How to impose a proper AC sinosidal electromagnetic wave on the system.

A picture of my system is also attached below.


1 Reply Last Post 2014年6月8日 GMT-4 13:14

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Posted: 1 decade ago 2014年6月8日 GMT-4 13:14
would appreciate some help guys
would appreciate some help guys

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