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power through scattering boundary condition

Posted May 4, 2014, 10:14 p.m. EDT Version 4.3 3 Replies

Alirza Maleki
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Hello all;

Im using scattering boundary condition as power source to illuminate my structure. Everything is Ok with that but I just don't know how to calculate the amount of power that is going through it. I mean by using ports you can define a specific amount of power trough them, but by scattering boundary condition you can define just the electric field and when I use regular formulas for calculating EM power and put the result as the amount of electric field the result is different, and it seems that its not that calculated amount of power. I would appreciate if somebody that knows about this problem could give some directions.

Thanks
Alireza
3 Replies Last Post Dec 3, 2014, 11:28 p.m. EST
Pu Zhang
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Posted: 1 decade ago May 5, 2014, 3:04 a.m. EDT
I don't know if scattering boundary condition is meant to be used as source, but I'm not surprised that the power is different, since it is not a simple electric field boundary condition per se. If you calculate the power in another way I think it is just fine.
I don't know if scattering boundary condition is meant to be used as source, but I'm not surprised that the power is different, since it is not a simple electric field boundary condition per se. If you calculate the power in another way I think it is just fine.
Alirza Maleki
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Posted: 1 decade ago May 5, 2014, 3:23 a.m. EDT
Hi Pu;

Thank you for your reply. Yes you are right, I mean using scattering boundary condition as a source for exciting a grating. Using exciting ports makes some problems for doing this model as there is a reflection of the grating that comes back to the port and changes the illuminations uniformity of grating. Am I right? By using the scattering boundary condition as the source this problem would have the least effect, at least the models show it. ! So, I was wondering if you know any other way to use the ports as source and letting the reflected field back to the source be passed away through the port?

Thanks
Hi Pu; Thank you for your reply. Yes you are right, I mean using scattering boundary condition as a source for exciting a grating. Using exciting ports makes some problems for doing this model as there is a reflection of the grating that comes back to the port and changes the illuminations uniformity of grating. Am I right? By using the scattering boundary condition as the source this problem would have the least effect, at least the models show it. ! So, I was wondering if you know any other way to use the ports as source and letting the reflected field back to the source be passed away through the port? Thanks
Seojun Lee
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Posted: 1 decade ago Dec 3, 2014, 11:28 p.m. EST
About the problem taking care of the reflection to the exciting port, as far as I know you might be able to use port + identity pair + PML. This method enables you to set the port in the middle of the simulation geometry, in contrast to the general case that we usually can't set the port in the boundary inside the simulation unless it is on the exterior boundary of the simulation. This method could be quite complicated if the simulation geometry is complex. I'm adding the address of the site that introducing the method.

srdjancomsol.weebly.com/proper-use-of-pmls-and-bcs-with-assemblies-2d.html

I'm also new to Comsol and I'm having the same problem about the reflection to the exciting port. I tried to use the method I described above, but it has not been going well. So, for now I'm just using the scattering boundary to excite the plane wave as you did. Anyway good luck on Comsoling!
About the problem taking care of the reflection to the exciting port, as far as I know you might be able to use port + identity pair + PML. This method enables you to set the port in the middle of the simulation geometry, in contrast to the general case that we usually can't set the port in the boundary inside the simulation unless it is on the exterior boundary of the simulation. This method could be quite complicated if the simulation geometry is complex. I'm adding the address of the site that introducing the method. http://srdjancomsol.weebly.com/proper-use-of-pmls-and-bcs-with-assemblies-2d.html I'm also new to Comsol and I'm having the same problem about the reflection to the exciting port. I tried to use the method I described above, but it has not been going well. So, for now I'm just using the scattering boundary to excite the plane wave as you did. Anyway good luck on Comsoling!

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