integrating a lookup table for frequency dependent variables

Hi everyone,

I have created a lookup table for frequency dependent values of epsilon_r.
This table includes two interpolation functions: one for the real part (eps_real) and the other for the imaginary part (eps_imag).

In the material browser, I tried to add these two functions as a sum (eps_real + eps_imag) for the expression of the relative permittivity. Unfortunately, this causes an error during computation.

I therefore assume that the way I tried to tackle my problem is not possible.
Does anyone know who to integrate values of an interpolation function of a lookup table into variables for frequency dependent materials?


Thank you.