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NaN or Inf found when solving linear system using SOR in RF Module

Posted Jan 14, 2015, 10:35 a.m. EST RF & Microwave Engineering Version 4.3 6 Replies

Niels Chen
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Hi everyone,

I am trying to simulate S parameters of a coplanar waveguide resonator between two lumped ports in RF Module, where frequency domain study is chosen. However, when I run the computation, an error of "UNDEFINED VALUE FOUND" occurs, with detail "NAN OR INF FOUND WHEN SOLVING LINEAR SYSTEM USING SOR".

Undefined value found.
- Detail: NaN or Inf found when solving linear system using SOR.

I compared the settings of my model with the built-in cascaded_cavity_filter model (which runs properly), but I could not find any difference.

Could anyone help me figure out what may cause the error? Due to extension error, I am not able to attach my model to this message.

Thanks in advance.

Niels
6 Replies Last Post Jun 1, 2016, 9:27 a.m. EDT
Sven Friedel COMSOL Employee

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Posted: 10 years ago Jan 19, 2015, 4:00 a.m. EST
Hi Niels,

I saw that your question has not yet been answered by the community.
If you would like to submit your model here, you can always reduce its size by executing
in the hrizontal Ribbon
Study > Delete all solutions
Mesh > Delete all meshes

As your school has a license under subscription, feel free to contact us also through
support@comsol.com

Best regards,
Sven Friedel

Hi Niels, I saw that your question has not yet been answered by the community. If you would like to submit your model here, you can always reduce its size by executing in the hrizontal Ribbon Study > Delete all solutions Mesh > Delete all meshes As your school has a license under subscription, feel free to contact us also through support@comsol.com Best regards, Sven Friedel
Niels Chen
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Posted: 10 years ago Jan 19, 2015, 4:58 a.m. EST
Hi Sven,

Thank you for your attention. I have got in touch with your colleagues through COMSOL support.

Best,
Niels
Hi Sven, Thank you for your attention. I have got in touch with your colleagues through COMSOL support. Best, Niels
Niels Chen
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Posted: 10 years ago Jan 19, 2015, 5:03 a.m. EST
COMSOL Supporting group says

"This typically happens in models where the frequency is too high for the waves to be properly resolved by the mesh".

Though this is not the case in my model, hopefully it will be helpful for others who encounter the "NaN or Inf found when solving linear system using SOR" error.
COMSOL Supporting group says "This typically happens in models where the frequency is too high for the waves to be properly resolved by the mesh". Though this is not the case in my model, hopefully it will be helpful for others who encounter the "NaN or Inf found when solving linear system using SOR" error.
Qiancheng Zhao
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Posted: 10 years ago Jan 21, 2015, 2:58 p.m. EST
Hi Niels,

Great thanks for sharing the solution.

Can you explain a lit bit more on how to change the mesh size? If the frequency is too high, then the wavelength is too short. Then should we use larger mesh size or smaller?

Thanks,
Hi Niels, Great thanks for sharing the solution. Can you explain a lit bit more on how to change the mesh size? If the frequency is too high, then the wavelength is too short. Then should we use larger mesh size or smaller? Thanks,
Niels Chen
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Posted: 10 years ago Jan 22, 2015, 3:33 a.m. EST
Hi Qiancheng,

As the mesh should resolve the shortest wavelength, if the frequency is too high, a finer mesh should be used. However, please notice that there may be other cause of this kind of error.

Good luck!

Regards,
Niels
Hi Qiancheng, As the mesh should resolve the shortest wavelength, if the frequency is too high, a finer mesh should be used. However, please notice that there may be other cause of this kind of error. Good luck! Regards, Niels
Shailesh Joshi
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Posted: 8 years ago Jun 1, 2016, 9:27 a.m. EDT
Hi

This post seems a bit old, but I thought I would share my experience as well. Meshing it fine does help but one thing which definitely resolved the issue was tweaking the material of the domains, for e.g. PEC to Copper etc.

Shailesh
Hi This post seems a bit old, but I thought I would share my experience as well. Meshing it fine does help but one thing which definitely resolved the issue was tweaking the material of the domains, for e.g. PEC to Copper etc. Shailesh

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