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Electrical Conductivity in the RF Module
Posted 1 août 2013, 08:06 UTC−4 RF & Microwave Engineering, Materials, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3a 2 Replies
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I have a question considering the setup of materials in the RF module. Comsol offers three different parameters to set up the materials in this module: the electrical conductivity, the relative permittivity and the relative permeability.
I want to simulate a nanodisk made of gold. Therefor, I read the scattering nanosphere model in the model library. In this model, the relative permittivity of the gold sphere is filled with the dielectric function of gold and the electrical conductivity is set to 0. It should be clear that the electrical conductivity of gold is not 0. What does that mean then? Is Comsol calculating the electrical conductivity then by itself using the dielectric function?
Best regards and thank you for your help.
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Maxwell wave equation contains complex-valued permittivity:
epsilon_c=epsilon-j*sigma/omega
(1) You can specify both “epsilon” and “sigma” to characterize electrical properties of metal.
(2) Alternatively, you can set “sigma” to zero and specify complex-valued number for “epsilon” to obtain the same value for “epsolin_c”.
Both ways result in the same wave equation and, therefore, lead to the same result. Comsol model library example for gold particle scattering uses the second approach to characterize properties of the gold.
Regards,
Sergei
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