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S-parameters simulation, Lossy conductor

Posted May 10, 2012, 4:42 p.m. EDT RF & Microwave Engineering Version 4.2a 3 Replies

Matthias Kofler
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Hello,

I am working on a model which should be used for s-parameters simulation. In my current simulations I assume a perfect electric conductor (lossy-free conductor). Now, I would like to define as lossy conductor e.g. copper, but after changing the I have troubles with the defined lumped ports. Furthermore, I want to run the s-parameter simulations using a lossy conductor with thickness. At the moment the conductor is more or less a boundary condition without thickness.
I think my description will be clearer if you see my attached model.

It would be of great help to me if somebody can give me an idea how to get those things running.

Best greets,
Matthias

Attachments:

3 Replies Last Post May 15, 2012, 11:07 a.m. EDT
Dennis Brown
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Posted: 1 decade ago May 11, 2012, 9:03 a.m. EDT
I don't believe comsol can do this as of ver 42a. Looking at the documentation for impedance boundary condition:

"The Impedance Boundary Condition

is used at boundaries where the field is known to penetrate only a short distance outside the boundary. This penetration is approximated by a boundary condition to avoid the need to include another domain in the model. Although the equation is identical to the one in the low-reflecting boundary condition, it has a different interpretation. The material properties are for the domain outside the boundary and not inside, as for low-reflecting boundaries."

You cannot really model interior traces currently. A fundamental limit of comsol.

If a comsol rep wants to show that this not true, please chime in and demonstrate. I would like to see this myself.

If you right clicked and added an IBC node to the emw intfc, it will not allow you to select the trace as a boundary condition. It will let you select the outer sides of your box though.

All of the models I have seen in the RF model gallery typically have PECs for interior traces/metal.


I don't believe comsol can do this as of ver 42a. Looking at the documentation for impedance boundary condition: "The Impedance Boundary Condition is used at boundaries where the field is known to penetrate only a short distance outside the boundary. This penetration is approximated by a boundary condition to avoid the need to include another domain in the model. Although the equation is identical to the one in the low-reflecting boundary condition, it has a different interpretation. The material properties are for the domain outside the boundary and not inside, as for low-reflecting boundaries." You cannot really model interior traces currently. A fundamental limit of comsol. If a comsol rep wants to show that this not true, please chime in and demonstrate. I would like to see this myself. If you right clicked and added an IBC node to the emw intfc, it will not allow you to select the trace as a boundary condition. It will let you select the outer sides of your box though. All of the models I have seen in the RF model gallery typically have PECs for interior traces/metal.
Matthias Kofler
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Posted: 1 decade ago May 11, 2012, 3:16 p.m. EDT
Hi Dennis,

I communicated to the Comsol Support concerning my request. They explained a way how to realize that but I didn't have time to try it yet.
I'm going to attempt it next week. I will let you know if I was able to run such a simulation.

Thanks for your response,

Matthias
Hi Dennis, I communicated to the Comsol Support concerning my request. They explained a way how to realize that but I didn't have time to try it yet. I'm going to attempt it next week. I will let you know if I was able to run such a simulation. Thanks for your response, Matthias
Dennis Brown
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Posted: 1 decade ago May 15, 2012, 11:07 a.m. EDT
Hi Mattias,

I think that I am wrong about being able to model interior traces.

Check this for an example. I was trying to help somebody else out and eventually it bugged me enough to try and figure out why.

www.comsol.com/community/forums/general/thread/28313/


Hi Mattias, I think that I am wrong about being able to model interior traces. Check this for an example. I was trying to help somebody else out and eventually it bugged me enough to try and figure out why. http://www.comsol.com/community/forums/general/thread/28313/

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