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Different results of S11 parameter for different mesh element sizes

Posted 20 mai 2019, 08:04 UTC−4 RF & Microwave Engineering, Mesh, Studies & Solvers Version 5.4 4 Replies

Suad
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Hi,

I have achieved two very different S11 parameter plots for the same patch antenna simulation at "extremelly coars" and "normal" element sizes of mesh. I attached these two results as image files to this question. "normal" one is more similar to the measurement results. But how can I be sure which element size is enough for me. Because, the finer element sizes are very heavy for my computer.

Thank you

4 Replies Last Post 21 mai 2019, 12:01 UTC−4
Robert Koslover Certified Consultant
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Posted: 6 years ago 20 mai 2019, 16:37 UTC−4
Updated: 6 years ago 20 mai 2019, 16:37 UTC−4

Well, you can be moderately more confident that the normal mesh is giving better results than the coarser mesh. You might want to also try models with different settings of discretization (linear, quadratic, etc.), or use a slow but stable iterative solver (if you aren't already), like GMRES with the SOR vector preconditioner, along with a relatively fine mesh, and then even consider a higher level of discretization (if you have enough memory), to achieve high accuracy. Regardless, use your finest mesh settings on the patch and its local substrate, but leave the surrounding space/volume at coarser mesh settings, to keep the computational size under control. Finally, also bear in mind that if you are modeling just one simple patch antenna, but are already running out of memory, then you are either using your memory rather wastefully in your model or have a very limited-capability computer. If the latter, you may want to think about upgrading your computer hardware.

-------------------
Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
Well, you can be moderately more confident that the normal mesh is giving better results than the coarser mesh. You might want to also try models with different settings of discretization (linear, quadratic, etc.), or use a slow but stable iterative solver (if you aren't already), like GMRES with the SOR vector preconditioner, along with a relatively fine mesh, and then even consider a higher level of discretization (if you have enough memory), to achieve high accuracy. Regardless, use your finest mesh settings on the patch and its local substrate, but leave the surrounding space/volume at coarser mesh settings, to keep the computational size under control. Finally, also bear in mind that if you are modeling just one simple patch antenna, but are already running out of memory, then you are either using your memory rather wastefully in your model or have a very limited-capability computer. If the latter, you may want to think about upgrading your computer hardware.
Suad
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Posted: 6 years ago 21 mai 2019, 03:19 UTC−4

Thank you for your answer Robert.

From your answer, I understand that I have to go to the details of the solver :( . This is bad news for me, because I thought I could simulate antennas by using classical instructions as in Application Gallery (https://www.comsol.com/models).

By the way my computer configuration is as follows: 64 Bit Intel Core i5 4590 CPU @ 3.30 GHz 4 GB RAM (DDR3)

Thank you for your answer Robert. From your answer, I understand that I have to go to the details of the solver :( . This is bad news for me, because I thought I could simulate antennas by using classical instructions as in Application Gallery (https://www.comsol.com/models). By the way my computer configuration is as follows: 64 Bit Intel Core i5 4590 CPU @ 3.30 GHz 4 GB RAM (DDR3)
Robert Koslover Certified Consultant
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Posted: 6 years ago 21 mai 2019, 11:35 UTC−4
Updated: 6 years ago 21 mai 2019, 11:34 UTC−4

You're welcome. By the way, I recommend you install a lot more RAM, if you can.

-------------------
Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
You're welcome. By the way, I recommend you install a *lot* more RAM, if you can.
Suad
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Posted: 6 years ago 21 mai 2019, 12:01 UTC−4

I'll try. Thanks again.

I'll try. Thanks again.

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