# Dielectric Modelling

This option specifies the model (method) used to define a dielectric medium.

## Frequency independent

The properties of the dielectric medium are specified as frequency independent.

Relative permittivity
Relative permittivity ${\epsilon }_{r}$ of the medium.
Dielectric loss tangent
Dielectric loss tangent $\mathrm{tan}\delta$ of the medium (this is an alternative way to specify the conductivity $\sigma$ — the two loss terms are related by $\mathrm{tan}\delta =\frac{\sigma }{\omega {\epsilon }_{r}{\epsilon }_{0}}$ and have different frequency behaviour).
Conductivity
Conductivity $\sigma$ in $\frac{1}{\Omega m}$ of the medium.

## Debye Relaxation

The relaxation characteristics of gasses and fluids at microwave frequencies are described by the Debye model. It has been derived for freely rotating spherical polar molecules in a predominantly non-polar background.

Relative static permittivity
Relative permittivity ${\epsilon }_{\text{s}}$ of the medium.
High frequency dielectric constant
High frequency dielectric constant ${\epsilon }_{\infty }$ of the medium.
Relaxation frequency
The relaxation frequency ${f}_{r}$ of the medium.

## Cole-Cole

The model is similar to the Debye model, but uses one additional parameter to describe the material.

Relative static permittivity
Relative static permittivity ${\epsilon }_{\text{s}}$ of the medium.
High frequency dielectric constant
High frequency dielectric constant ${\epsilon }_{\infty }$ of the medium.
Relaxation frequency
The relaxation frequency ${f}_{r}$ of the medium
Attenuation factor
Attenuation factor $\alpha$ of the medium.

## Havriliak-Negami

This is a more general model and should be able to successfully model liquids, solids and semi-solids.

Relative static permittivity
Relative static permittivity ${\epsilon }_{\text{s}}$ of the medium.
High frequency dielectric constant
High frequency dielectric constant ${\epsilon }_{\infty }$ of the medium.
Relaxation frequency
The relaxation frequency ${f}_{r}$ of the medium
Attenuation factor
Attenuation factor $\alpha$ of the medium.
Phase factor
Phase factor $\beta$ of the medium.

## Djordjevic-Sarkar

This is a particularly well suited broadband model for composite dielectrics.

Variation of relative permittivity
Variation of the relative permittivity $△\epsilon$ of the medium.
Relative high frequency permittivity
Relative high frequency permittivity ${\epsilon }_{\infty }$ of the medium.
Conductivity
Conductivity $\sigma$ in $\frac{1}{\Omega m}$ of the medium.
Lower limit of angular frequency
The lower limit of the angular frequency for the medium, ${\omega }_{1}$ of the medium.
Upper limit of angular frequency
The upper limit of the angular frequency for the medium, ${\omega }_{2}$ of the medium.

## Specify points in the *.pre file (linear interpolation)

This is a particularly well suited broadband model for composite dielectrics.

Frequency
The frequency for the specific data point.
Relative permittivity
Relative permittivity ${\epsilon }_{r}$ of the medium at a specific frequency.
Dielectric loss tangent
Dielectric loss tangent $\mathrm{tan}\delta$ of the medium (this is alternative way to specify the conductivity $\sigma$ — the two loss terms are related by $\mathrm{tan}\delta =\frac{\sigma }{\omega {\epsilon }_{r}{\epsilon }_{0}}$ and have different frequency behaviour).
Conductivity
Conductivity $\sigma$ in $\frac{1}{\Omega m}$ of the medium.