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Meshing and solving for very small elements
Posted Nov 22, 2010, 3:21 p.m. EST 3 Replies
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Hello,
I am very new to COMSOL and my goal is to be able to simulate a very small capacitor in 3D using specific materials. I have had a lot of trouble doing that so right now I am trying to create a 2D simulation of a very small capacitor as practice. The dimensions of each plate in meters is roughly 1.2e-4 by 1e-7, and there is a 1e-6 gap between these plates. When I mesh my design I get a very odd looking mesh, and then when I solve the problem it does not give the right result. Is there something wrong with making such a small device? Seeing as the test area is not very large I assumed I would be able to simulate a small region, because compared to it's environment the capacitor itself is not very small, and so it won't result in a singular matrix.
I appreciate any help you might have.
Thank you,
Michael Purdy
I am very new to COMSOL and my goal is to be able to simulate a very small capacitor in 3D using specific materials. I have had a lot of trouble doing that so right now I am trying to create a 2D simulation of a very small capacitor as practice. The dimensions of each plate in meters is roughly 1.2e-4 by 1e-7, and there is a 1e-6 gap between these plates. When I mesh my design I get a very odd looking mesh, and then when I solve the problem it does not give the right result. Is there something wrong with making such a small device? Seeing as the test area is not very large I assumed I would be able to simulate a small region, because compared to it's environment the capacitor itself is not very small, and so it won't result in a singular matrix.
I appreciate any help you might have.
Thank you,
Michael Purdy
3 Replies Last Post Nov 23, 2010, 5:25 a.m. EST
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Posted:
1 decade ago
Hi
nothing wrong with small items,
but you must also check the graphical and physical resolutions in use, these are set/located differently for 3.5 and 4.
Typically the graphical resolution is some 1e-5 or 10 um, you must turn it down to 1nm or 1e-9, or 1E-8 I would say for your case, that should help.
--
Good luck
Ivar
nothing wrong with small items,
but you must also check the graphical and physical resolutions in use, these are set/located differently for 3.5 and 4.
Typically the graphical resolution is some 1e-5 or 10 um, you must turn it down to 1nm or 1e-9, or 1E-8 I would say for your case, that should help.
--
Good luck
Ivar
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Posted:
1 decade ago
Hi Ivar,
I am sorry but I am very new with COMSOL. I have tried to look up what you mean by the graphical and physical resolutions but I'm not sure I understand. I have tried changing my meshing resolutions which does not seem to help.
Thanks for all of your help so far though : )
Michael
I am sorry but I am very new with COMSOL. I have tried to look up what you mean by the graphical and physical resolutions but I'm not sure I understand. I have tried changing my meshing resolutions which does not seem to help.
Thanks for all of your help so far though : )
Michael
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Posted:
1 decade ago
Hi
COMSOL works first on your geometry, check the Geometry node, Geometry Settings page: "Default relative repair tolerance".
If you mport a geometry you have also other seetings, and at the end the "Relative repair tolerance" in the Form union (fin) subnode at the end of the geometry section
These values should be at least smaller than your "small features"
--
Good luck
Ivar
COMSOL works first on your geometry, check the Geometry node, Geometry Settings page: "Default relative repair tolerance".
If you mport a geometry you have also other seetings, and at the end the "Relative repair tolerance" in the Form union (fin) subnode at the end of the geometry section
These values should be at least smaller than your "small features"
--
Good luck
Ivar