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Complex permittivity, permeability and conductivity

Posted Feb 7, 2018, 6:15 p.m. EST 2 Replies

Peter H
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I am modeling materials-photons interactions. I have created a new custom material which I wish to completely define using complex valued permittivity and permeability numbers and I wish to confirm two things:

1) is the way I have entered these complex values below correct, given that ur, ui, er and ei are defined in my Global Parameters?

Link to image: https://imgur.com/a/NKqAi

2) Even though the physics module I'm using is sampling the "electrical conductivity", does the complex value of permittivity ALWAYS overwrite the suggested imaginary value of permmitvity implied by the conductivity? Stated otherwise, when imaginary permittivity is defined is the conductivity field irrelevant?

Many thanks for the help!

2 Replies Last Post Feb 8, 2018, 12:05 p.m. EST
Sergei Yushanov Certified Consultant
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Posted: 7 years ago Feb 8, 2018, 8:45 a.m. EST

Peter,

1) Yes, permittivity and permeability are defined correctly.

2) No, complex value of permittivity doesn't overwrite losses related to conductivity. When you define complex part of permittivity and non-zero conductivity at the same time, it means that total loss is a superposition of polarization loss and conductive loss. This is because permittivity and conductivity enter Maxwell equation not independently but in combination (eps-jsigma/omega)=[(eps'-jeps")-j*sigma/omega].

Good explanation of alternative ways of medium characterization is given in the Table on p. 22 of the following textbook: http://www.sembahome.org/geg/files/2016/02/electrodinamicaprimeraparte.pdf

Regards,

Sergei

Peter, 1) Yes, permittivity and permeability are defined correctly. 2) No, complex value of permittivity doesn't overwrite losses related to conductivity. When you define complex part of permittivity and non-zero conductivity at the same time, it means that total loss is a superposition of polarization loss and conductive loss. This is because permittivity and conductivity enter Maxwell equation not independently but in combination (eps-j*sigma/omega)=[(eps'-j*eps")-j*sigma/omega]. Good explanation of alternative ways of medium characterization is given in the Table on p. 22 of the following textbook: http://www.sembahome.org/geg/files/2016/02/electrodinamicaprimeraparte.pdf Regards, Sergei
Peter H
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Posted: 7 years ago Feb 8, 2018, 12:05 p.m. EST
Updated: 7 years ago Feb 8, 2018, 12:14 p.m. EST

Hello, Sergei, I was hoping you would spot my question based on your previous replies to similar questions.

I see the parameterization you are talking about in the textbook and that clears up my misunderstanding -- other sources I was working from weren't as clear.

Thank you,

Peter

Hello, Sergei, I was hoping you would spot my question based on your previous replies to similar questions. I see the parameterization you are talking about in the textbook and that clears up my misunderstanding -- other sources I was working from weren't as clear. Thank you, Peter

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