Menu

Discussion Forum

New Discussion
Filter

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Problem when simulating nanowire absorption

Posted May 24, 2011, 4:27 a.m. EDT RF & Microwave Engineering, Studies & Solvers 4 Replies

Olivier Demichel
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hy all,

I'm simulating the absorption of a nanowire in vaccum. I started with a 2D model in the RF module. My geometry is a nanowire in vacuum surrounded by cartesian air-PML. I solved the problem for the scattered field. The incident field propagates along the y direction and is either x or z polarized.

I have no problem with the x-polarization, however when I solve the problem for the z-polarized field, the scattered field is not well absorbed by the PML (see fig in attachment) and it does not change if I increase the size of the PML and/or the mesh size.

Can somebody explain why ?

Furthermore, I'm trying to simulate the absorption in the 3D geometry and to reduce the model size, I want to model only a quarter of a nanowire, which boundary condition should be apply ? I found that perfect electric/magnetic BC are not rigorously correct in that case. Is there a way to impose different BCs on each component of the fields on the surface ?

Thanks a lot !

Olivier
4 Replies Last Post Oct 24, 2016, 4:01 a.m. EDT
Shakeeb Bin Hasan
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago May 27, 2011, 8:35 a.m. EDT
I cannot say if this will completely eliminate your problem, but your PMLs don't seem to be properly drawn. I would suggest you to have a look at the tutorial model "Dielectric scattering" in which they do exactly what you are trying to do here.

All the best
I cannot say if this will completely eliminate your problem, but your PMLs don't seem to be properly drawn. I would suggest you to have a look at the tutorial model "Dielectric scattering" in which they do exactly what you are trying to do here. All the best
Tom Celano
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jun 17, 2011, 1:19 p.m. EDT
I found that having the PMLs intersect eachother on the outside surface works well, you could also try putting a scattering boundary on the outside of each of the PMLs. I am also trying to model nanowire absorption and I was wondering what you were using to induce the electric field down the sample. I tried using a scattering boundary but this requires an open face without a PML, and for some reason when I tried using a port at the inner face of a PML it did not work.

Hope this helps.
I found that having the PMLs intersect eachother on the outside surface works well, you could also try putting a scattering boundary on the outside of each of the PMLs. I am also trying to model nanowire absorption and I was wondering what you were using to induce the electric field down the sample. I tried using a scattering boundary but this requires an open face without a PML, and for some reason when I tried using a port at the inner face of a PML it did not work. Hope this helps.
Olivier Demichel
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jun 18, 2011, 3:57 a.m. EDT
Hey Tom,
you just have to use the "solve for scattered field" mode in the settings of the emw physics. This will allow you to define an incident electric field in the non-pml regions.
have fun
Olivier
Hey Tom, you just have to use the "solve for scattered field" mode in the settings of the emw physics. This will allow you to define an incident electric field in the non-pml regions. have fun Olivier
M.H.Elshorbagy
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 8 years ago Oct 24, 2016, 4:01 a.m. EDT
Hi Olivier

Could you please tell me how to set x polarization in 2D

Thanks in advance

M.H.Elshorbagy
Hi Olivier Could you please tell me how to set x polarization in 2D Thanks in advance M.H.Elshorbagy

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content