Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted:
1 decade ago
23.11.2012, 09:43 GMT-5
Hi
indeed that is quite some RAM, but depending on how many DoF you have it might not be enough. Have you checked what kind of RAM you need ? there is a KB knowledge base document discussing DoFs and approx RAM and mesh types
--
Good luck
Ivar
Hi
indeed that is quite some RAM, but depending on how many DoF you have it might not be enough. Have you checked what kind of RAM you need ? there is a KB knowledge base document discussing DoFs and approx RAM and mesh types
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
23.11.2012, 10:50 GMT-5
I am impressed by your immediate response. Thank you very much.
My structure is 3D and has 663000 elements.
I have 7 different dielectric layers which have same length and width but very different height. For exaample three of them are X nm , 3 of them 4*X nm and 1 layer of 30*X nm. It is obvious that there is a big ratio between the height that is why I use finer and extra fine mesh, otherwise I have some instabilities in the solver. I have used swept meshing for each boundary-domain. Furthermore, the whole structure is excited by two lumped ports from 1Ghz to 10Ghz
I suppose that I will find this knowledge base in manual. If I am wrong please tell me where to find it.
Thank you again.
I am impressed by your immediate response. Thank you very much.
My structure is 3D and has 663000 elements.
I have 7 different dielectric layers which have same length and width but very different height. For exaample three of them are X nm , 3 of them 4*X nm and 1 layer of 30*X nm. It is obvious that there is a big ratio between the height that is why I use finer and extra fine mesh, otherwise I have some instabilities in the solver. I have used swept meshing for each boundary-domain. Furthermore, the whole structure is excited by two lumped ports from 1Ghz to 10Ghz
I suppose that I will find this knowledge base in manual. If I am wrong please tell me where to find it.
Thank you again.
Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
23.11.2012, 13:41 GMT-5
Hi
if I replied rapidly it was just fair luck, I was waiting 30 sec for Comsol to finsih a solver sequence, so I took a visit to the Forum ;)
Now 600kDoF is not that much, why should that give RAM issues when you have so much ?
OK if you have fine layers the meshing is tricky, and at high RF frequencies you need to have also many elements per wavelength * index of refraction.
Have you considered if it's possible to transform some of the thin layers in "surface physics" ? sometimes this helps, else you would need N elements in the thickness, at least enough to solve your depedent variables, and their slopes
--
Good luck
Ivar
Hi
if I replied rapidly it was just fair luck, I was waiting 30 sec for Comsol to finsih a solver sequence, so I took a visit to the Forum ;)
Now 600kDoF is not that much, why should that give RAM issues when you have so much ?
OK if you have fine layers the meshing is tricky, and at high RF frequencies you need to have also many elements per wavelength * index of refraction.
Have you considered if it's possible to transform some of the thin layers in "surface physics" ? sometimes this helps, else you would need N elements in the thickness, at least enough to solve your depedent variables, and their slopes
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
29.11.2012, 12:54 GMT-5
Thank you very much for your response. The problem was that I had a lot of elements in swept distributiion. So this problem has been solved. I would like to ask you another question if it is possible. I would like to calculate the impedance of this multilayer, what would be the appropriate boundary conditions?
Thanks in advance.
Thank you very much for your response. The problem was that I had a lot of elements in swept distributiion. So this problem has been solved. I would like to ask you another question if it is possible. I would like to calculate the impedance of this multilayer, what would be the appropriate boundary conditions?
Thanks in advance.
Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
30.11.2012, 02:03 GMT-5
Hi
for quick impedance calculations, you should study the lumped port / terminal BCs in the doc and compare these to the electric potential or electric current BC (which are for field variables BC values, and not scalars)
--
Good luck
Ivar
Hi
for quick impedance calculations, you should study the lumped port / terminal BCs in the doc and compare these to the electric potential or electric current BC (which are for field variables BC values, and not scalars)
--
Good luck
Ivar