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What is the diffrence btw PML and 'scattering boundary condition'?

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Setting a subdomain as PML and a boundary condition as scattering boundary can be used alternatively?
I checked it for one tutorial expamle( dielectric scattering PML ) and almost identical result is produced.

2 Replies Last Post Jan 12, 2011, 6:01 p.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Dec 26, 2010, 2:41 p.m. EST
Hi

if you read the doc on RF for v4.1 you will get a rather ind epth explanation I believe:

in very short:

A BOUNDARY "port" or a "scattering" condition are to define absorbing/source electric boundaries, in a distributed or a lumped (port) , but in well defined way, this means among other that the wave can travel in both direction from or through the boundary.

While the PML is a DOMAIN feature simulating an infinite domain where ANY wave can propagate and dissapear (without being reflected back)

--
Good luck
Ivar
Hi if you read the doc on RF for v4.1 you will get a rather ind epth explanation I believe: in very short: A BOUNDARY "port" or a "scattering" condition are to define absorbing/source electric boundaries, in a distributed or a lumped (port) , but in well defined way, this means among other that the wave can travel in both direction from or through the boundary. While the PML is a DOMAIN feature simulating an infinite domain where ANY wave can propagate and dissapear (without being reflected back) -- Good luck Ivar

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Posted: 1 decade ago Jan 12, 2011, 6:01 p.m. EST
Sir

If I want to caculate the Q factor of the whispering gallery mode in the 2D optical circular disk microdisk, what kind of boundary condtion shall I use? The Q factor is just limited to the radiation if I dont consider the absorption of the material .
Another question is shall I use the eigenfrequency analysis to calculate the eigenvalue? After that ,I chose the eigenvalues with small real parts(which with high Q) and calculate the Q factor in the which the imaginary part is divided by the real part. Is the method correct?

Thank you


Hi

if you read the doc on RF for v4.1 you will get a rather ind epth explanation I believe:

in very short:

A BOUNDARY "port" or a "scattering" condition are to define absorbing/source electric boundaries, in a distributed or a lumped (port) , but in well defined way, this means among other that the wave can travel in both direction from or through the boundary.

While the PML is a DOMAIN feature simulating an infinite domain where ANY wave can propagate and dissapear (without being reflected back)

--
Good luck
Ivar


Sir If I want to caculate the Q factor of the whispering gallery mode in the 2D optical circular disk microdisk, what kind of boundary condtion shall I use? The Q factor is just limited to the radiation if I dont consider the absorption of the material . Another question is shall I use the eigenfrequency analysis to calculate the eigenvalue? After that ,I chose the eigenvalues with small real parts(which with high Q) and calculate the Q factor in the which the imaginary part is divided by the real part. Is the method correct? Thank you [QUOTE] Hi if you read the doc on RF for v4.1 you will get a rather ind epth explanation I believe: in very short: A BOUNDARY "port" or a "scattering" condition are to define absorbing/source electric boundaries, in a distributed or a lumped (port) , but in well defined way, this means among other that the wave can travel in both direction from or through the boundary. While the PML is a DOMAIN feature simulating an infinite domain where ANY wave can propagate and dissapear (without being reflected back) -- Good luck Ivar [/QUOTE]

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