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complex relative permittivity

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I need to enter a complex relative permittivity into material settings - can I do this and if so, how? The value is -9.96+0.82i.

Many thanks.

2 Replies Last Post 27 mars 2013, 01:48 UTC−4

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Posted: 1 decade ago 17 juin 2010, 18:40 UTC−4
Yes, just enter it as the value for epsilonr and it should work.

But be aware that COMSOL uses the opposite convention for imaginary parts that a lot of the literature uses, such that a lossy material has a negative imaginary part of epsilon. So you should probably enter -9.96-0.82i.

Yes, just enter it as the value for epsilonr and it should work. But be aware that COMSOL uses the opposite convention for imaginary parts that a lot of the literature uses, such that a lossy material has a negative imaginary part of epsilon. So you should probably enter -9.96-0.82i.

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Posted: 1 decade ago 27 mars 2013, 01:48 UTC−4
Does COMSOL define the complex relative permittivity in every version, especially in 4.3, as

epsilon = epsilon_real - j*repsilon_imag ?


I had to create a lookup table for my simulation and initially typed in
epsilon = epsilon_real - j*repsilon_imag .

Now I'm wondering whether it should not have been
epsilon = epsilon_real + j*repsilon_imag .
Does COMSOL define the complex relative permittivity in every version, especially in 4.3, as epsilon = epsilon_real - j*repsilon_imag ? I had to create a lookup table for my simulation and initially typed in epsilon = epsilon_real - j*repsilon_imag . Now I'm wondering whether it should not have been epsilon = epsilon_real + j*repsilon_imag .

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