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Exciting a meta-surface with a point source
Posted 5 janv. 2015, 12:25 UTC−5 RF & Microwave Engineering Version 4.4 2 Replies
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Hi there,
I'm completely new to COMSOL, so I still struggle with it a lot. Bear with me! I've already looked in the existing discussions but found nothing helpful.
What I want to do is model the power flow over a metal-dielectric patterned surface (it's patterned with complimentary split ring resonators or CSRRs). I've already produced a model that solves the eigenmodes of the surface using floquet boundary conditions, which produces the correct result for what the resonant frequency of the material should be.
However, I need to model what the power flow looks like on this surface. Ideally, what I want to do is excite the surface with a point source electric field. But how do I do that?
I should mention, if I don't use periodic boundary conditions, I think I'm going to struggle computationally. The CSRRs I'm working with are spaced along a 2mm square pitch and the materials I'm investigating are A3-sized surfaces covered with these. So I sure couldn't model the whole material.
Any help at all is immensely appreciated.
I'm completely new to COMSOL, so I still struggle with it a lot. Bear with me! I've already looked in the existing discussions but found nothing helpful.
What I want to do is model the power flow over a metal-dielectric patterned surface (it's patterned with complimentary split ring resonators or CSRRs). I've already produced a model that solves the eigenmodes of the surface using floquet boundary conditions, which produces the correct result for what the resonant frequency of the material should be.
However, I need to model what the power flow looks like on this surface. Ideally, what I want to do is excite the surface with a point source electric field. But how do I do that?
I should mention, if I don't use periodic boundary conditions, I think I'm going to struggle computationally. The CSRRs I'm working with are spaced along a 2mm square pitch and the materials I'm investigating are A3-sized surfaces covered with these. So I sure couldn't model the whole material.
Any help at all is immensely appreciated.
2 Replies Last Post 15 janv. 2015, 19:15 UTC−5
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Posted:
10 years ago
Emily,
a point source is mostly not a good approach because it creates a singularity. In the RF module, you could try to connect a lumped port to some kind of feed electrode on your structure. Electric and magnetic point dipoles are also available. They don't create singularities.
Cheers
Edgar
--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
a point source is mostly not a good approach because it creates a singularity. In the RF module, you could try to connect a lumped port to some kind of feed electrode on your structure. Electric and magnetic point dipoles are also available. They don't create singularities.
Cheers
Edgar
--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Please login with a confirmed email address before reporting spam
Posted:
10 years ago
Are you sure you want a "point source electric field" -- whatever that is? A point source of an electric field is a point charge. Probably not what you want.
I suppose you could mean an electric dipole. You can make one of these pretty easy with a lumped port, but again, I'm not sure this is what you want.
Maybe what you want is a plane wave? Or a spherical wave? Are you illuminating the structure with light or RF in a frequency domain study? That would be plane waves.
The usual way to illuminate some structure with waves is to use the scattered field formulation. Basically you write an equation for the field everywhere pretending the structure wasn't there. You can make this whatever you want. Typically it would be a plane wave filling the region. COMSOL calculates the scattered field created when your structure IS there. You'll typically surround everything with slabs of PML.
If I'm on the right track, I can give you some more hints. There are several example models that use scattered fields, PML, and plane waves.
I suppose you could mean an electric dipole. You can make one of these pretty easy with a lumped port, but again, I'm not sure this is what you want.
Maybe what you want is a plane wave? Or a spherical wave? Are you illuminating the structure with light or RF in a frequency domain study? That would be plane waves.
The usual way to illuminate some structure with waves is to use the scattered field formulation. Basically you write an equation for the field everywhere pretending the structure wasn't there. You can make this whatever you want. Typically it would be a plane wave filling the region. COMSOL calculates the scattered field created when your structure IS there. You'll typically surround everything with slabs of PML.
If I'm on the right track, I can give you some more hints. There are several example models that use scattered fields, PML, and plane waves.