# Frequency Dependent Dielectrics

Define a frequency-dependent medium to use in your model or to add to the media library.

The following frequency-dependent definitions are supported:

- Debye relaxation
- Use this method to describe the relaxation characteristics of gasses and fluids at microwave frequencies. It is derived for freely rotating spherical polar molecules in a predominantly non-polar background.
- Cole-Cole
- This method is similar to the Debye relaxation but makes use of an additional parameter to describe the model.
- Havriliak-Negami
- Use this method to model liquids, solids and semi-solids.
- Djordjevic-Sarkar
- Use this method for composite dielectrics.
- Frequency List
- Use this method to define a frequency-dependent dielectric by specifying data points at a range of frequencies. The values for the dielectric properties are linearly interpolated to obtain the dielectric properties at frequency points other than specified.