comsol permittivity

Hi All,

I have a problem with entering complex permittivity. I have permittivity values for such a material from a formula, it has negative real and positive imaginary part. According to some support cases, it says imaginary part of permittivity has to be negative for a lossy material.

How should I enter that such a complex permittivity?

Thanks in advance,

The sign + or - depends the time factor.

Hi,

I know it is because of the sign convention, but still not sure about how to type in Comsol. The values from Drude model, and how it is defined in books.

thanks,