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Error in Mesh

Posted Apr 28, 2018, 1:16 a.m. EDT RF & Microwave Engineering 1 Reply

Hasanain Abdulhadi
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I have a problem when doing a model for microstrip patch antenna. I got the following error

**[[A problem occurred when building mesh feature 'Free Tetrahedral 1'. The current physics settings induce a mesh requirement of about 700 elements per m². Trying to fulfill this requirement may cause out of memory errors or process locking. Switching to user-controlled mesh. Please review mesh settings carefully before building the user-controlled mesh, or switch back to physics-controlled mesh and change physics settings.]] ** The physics that I have worked on is Electromagnetic Waves, Frquency and the study is frquency domain. Also, RAM of my computer is 16 GB, and the processor is 3.4 GB core i7. I hope if it is possible to explain the problem for me and how I could fix it. Thank you in advance.

1 Reply Last Post May 2, 2018, 1:20 p.m. EDT
Robert Koslover Certified Consultant
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Posted: 7 years ago May 2, 2018, 1:20 p.m. EDT
Updated: 7 years ago May 2, 2018, 1:22 p.m. EDT

You need to make your mesh fine enough to be able to represent: (1) the waves in detail in places where they matter, and (2) the geometry in detail in places where it matters. You can control the mesh by changing to a user-controlled mesh. Don't just let Comsol determine the mesh densities for you. The Comsol software isn't really very good at guessing what you actually need for most RF and antenna problems. Instead, use your own brain/knowledge about the patch antenna to recognize where you need a fine mesh and where you don't. Look up how to set mesh values manually in the Help system. There is a lot you can do. Hint: mesh the patch itself and the dielectric directly under it relatively finely (e.g., lambda/20 or finer), but you can mesh other parts of the computational volume much more coarsely (e.g., lambda/6) without difficulties. You can also set the discetization of the elements. Comsol will default to quadratic, but you can save memory if necessary by using linear. You can also choose your solvers differently (iterative ones are less stable and often slower, but use less RAM, while the direct ones are faster, but use more RAM).

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
You need to make your mesh fine enough to be able to represent: (1) the waves in detail in places where they matter, and (2) the geometry in detail in places where it matters. You can control the mesh by changing to a user-controlled mesh. Don't just let Comsol determine the mesh densities for you. The Comsol software isn't really very good at guessing what you actually need for most RF and antenna problems. Instead, use your own brain/knowledge about the patch antenna to recognize where you need a fine mesh and where you don't. Look up how to set mesh values manually in the Help system. There is a lot you can do. Hint: mesh the patch itself and the dielectric directly under it relatively finely (e.g., lambda/20 or finer), but you can mesh other parts of the computational volume much more coarsely (e.g., lambda/6) without difficulties. You can also set the discetization of the elements. Comsol will default to quadratic, but you can save memory if necessary by using linear. You can also choose your solvers differently (iterative ones are less stable and often slower, but use less RAM, while the direct ones are faster, but use more RAM).

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