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Defining a permittivity and permeability tensor in the RF module
Posted 20.06.2012, 15:32 GMT-4 RF & Microwave Engineering Version 4.2a 6 Replies
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I'm relatively new to Comsol, I'd like to model an anisotropic material in comsol, however my material should have a permeability and permittivity that are tensors as opposed to scalars, and I am unsure how to proceed.
Under Materials, Comsol allows you to input the chosen permittivity and permeability, but as constants:( Please any help or insight would be much appreciated.
-Thanks,
Kene
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have you set your physics node to anisotropic materials ?
Then COSMOL will choose tensor values, or request that you define them in the material node
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Good luck
Ivar
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I also want to simulate anisotropic media. Can anyone please elaborate the node thing? How can I do this in Comsol. I have tried but fail. I need discussion on this.
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there are a few ways:
a) you define your materials properties (nodes) accordingly
b) you define it in the Physics sub node
Normally anisotropy is defined with respect to a given coordinate system that might not be the default Cartesian one of your model, therefore often you must also define a Coordinate system and refer to the correct coordinates, which might by something like sys2.r, sys2.phi ...
As I find it very easy to get the anisotropic coordinates wrong, I do always plot the new coordinate system and the tensor values in a specific dedicated plot, for that you must set up your Solver, do an "Get Initial Values" and make a coordinate plot + a plot of your tensor values in the desired coordinate system
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Good luck
Ivar
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I want to study the behavior of electromagnetic wave at the interface of two different media, one is isotropic and the other is anisotropic. Please do more discussion with me.
I will really appreciate your cooperation. My email is waqasmahmoodqau@gmail.com
Please illustrate me in detail.
Regards,
Waqas.
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You cannot change the equation in the equation window there, but you may adapt the underlying equation used by COMSOL, however then you really must understand all the details under the hood! To start you need to turn "on" the "Equation view" in the preferences, and in the same time the other Advanced tabs too. But it's tricky, as there are many relationships, depending how you define your physics.
The cleanest way is to use the global mathematical entry, instead of the standard physics, and rewrite your physics your way. There is also the Model Builder, but its rather heavy if you do not have got a good training (I have tried a few times but not succeeded to become an expert in that interesting part of COMSOL, yet)
I'm only answering COMSOL questions, when I manage, and find the time, here on the Forum. Otherwise I'm getting in conflict with my own job as systems developer and simulation consultant :)
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Good luck
Ivar