CST2013: Material Parameters: default - Dispersion

Modeling: MaterialsNew/EditNew MaterialDispersion
Edit Object Properties (navigation tree: Materials:material1PropertiesDispersion)

This is a dialog page of the Material Parameters dialog box.

On this dialog page various dispersion models for the permittivity as well as for the permeability are available, representing different frequency dependent material formulations. Except for the magnetic gyrotropic behavior for biased ferrites, all models are also valid for an anisotropic material type.

Please note that corresponding to common literature the input parameters distinguish between angular frequencies indicated by the unit "rad/s" (e.g. resonance frequencies) and non-periodic frequency values in "1/s" (e.g. damping or collision frequencies).

Please see the Material Overview (HF) page for more detailed information about the different dispersion models.

Dielectric dispersion frame

Dispersion model: Here, different dielectric dispersion models can be chosen, each definable by a different set of specific material properties.

The first material parameter for all dielectric dispersions models is the epsilon infinity value, representing the high frequency limit of the permittivity.

Debye 1^st order:  The first order Debye dispersion describes a material relaxation process, determined by the relaxation time and the epsilon static value.

Debye 2^nd order: The second order Debye dispersion describes a superposed relaxation process given by the summation of two separate first order Debye models. The corresponding parameters are the two relaxation times as well as both epsilon static values.

Drude: The Drude dispersion model describes the dielectric behavior of plasma material, determined by the plasma frequency and the collision frequency representing damping effects. It is also possible to model a dependency of the instantaneous plasma frequency on the local electric field. This dependency introduces some non linear effect to the material, actually describing a non-uniform space dependent material. The additional parameters to be specified are the electric breakdown and the plasma maintenance frequency. Please see the Material Overview (HF) page for more detailed information about the meaning of these parameters and their relationship with the plasma model.

Lorentz:  The Lorentz dispersion model describes a material resonance process, determined by the epsilon static value, the resonance frequency and the damping factor.

Gyrotropic: The electric gyrotropic or so-called gyroelectric dispersion behavior is relevant for magnetized plasma media. The material parameters comprise the plasma frequency and the collision frequency as for the Drude dispersion. In addition, the cyclotron frequency and the biasing direction describe the effect of the homogeneous biasing field. Note that this material dispersion is not selectable for anisotropic material settings.

General 1^st order:  For a detailed information, see Material Overview.

General 2^nd order:  For a detailed information, see Material Overview.

Nonlinear 2^nd order:  The Nonlinear second order model describes a nonlinear material with second order dependency on the field. It is determined by the chi2 susceptibility coefficient.

Nonlinear 3^rd order:  The Nonlinear third order model describes a nonlinear material with third order dependency on the field. It is determined by the chi3 susceptibility coefficient.

Nonlinear Kerr:  The Nonlinear Kerr model describes a nonlinear material with third order dependency on the field. The instantaneous susceptibility follows a time relaxation process similar to a Debye model. The model is determined by the chi3 infinity and chi3 static susceptibility coefficients and by the relaxation time.

Nonlinear Raman:   The Nonlinear Raman model describes a nonlinear material with third order dependency on the field. The instantaneous susceptibility follows a time resonance process similar to a Lorentz model. The model is determined by the chi3 infinity and chi3 static susceptibility coefficients and by the resonance frequency and the damping factor.

User:  The dispersion fit is based either on a constant conductivity, general 1^st order, general 2^nd order or a general n^th order model. A list of eps' eps'' values can be defined by different frequency points by pressing the Dispersion List button.

Magnetic dispersion frame

Dispersion model: Here, different magnetic dispersion models can be chosen, each definable by a different set of specific material properties.

The first material parameter for all magnetic dispersions models is the mue infinity value, representing the high frequency limit of the permeability.

Debye 1^st order:  The first order Debye dispersion describes a material relaxation process, determined by the relaxation time and the mue static value.

Debye 2^nd order: The second order Debye dispersion describes a superposed relaxation process given by the summation of two separate first order Debye models. The corresponding parameters are the two relaxation times as well as both mue static values.

Drude: The description of this dispersion model corresponds to that of the dielectric material above. However, here this model offers just the possibility to define a specialized dispersion curve, the parameters plasma and collision frequency have no exact physical equivalence.

Lorentz:  The Lorentz dispersion model describes a material resonance process, determined by the mue static value, the resonance frequency and the damping factor.

Gyrotropic: The magnetic gyrotropic or so-called gyromagnetic dispersion behavior is relevant for ferrite materials that are magnetized up to saturation by a homogeneous static magnetic field. The corresponding parameters can be defined either in the Gauss or SI unit system, which are selectable in the Parameter conversion frame below.

In Gauss units, they are given by the  Landé factor, saturation magnetization (4 Pi M), the resonance line width representing the damping effects and finally the external applied magnetic field vector (x,y,z).

Using SI units as the input system instead, the parameters are given by the Larmor frequency, the gyrotropic frequency, the damping factor and finally the unit vector for the biasing direction (x,y,z). Note that this material dispersion is not selectable for anisotropic material settings.

See the Material Overview (HF) for a description of inhomogeneously biased ferrites.

General 1^st order:  For a detailed information see Material Overview.

General 2^nd order:  For a detailed information see Material Overview.

Nonlinear 2^nd order:  The Nonlinear second order model describes a nonlinear material with second order dependency on the field. It is determined by the chi2 susceptibility coefficient.

Nonlinear 3^rd order:  The Nonlinear third order model describes a nonlinear material with third order dependency on the field. It is determined by the chi3 susceptibility coefficient.

Nonlinear Kerr:  The Nonlinear Kerr model describes a nonlinear material with third order dependency on the field. The instantaneous susceptibility follows a time relaxation process similar to a Debye model. The model is determined by the chi3 infinity and chi3 static susceptibility coefficients and by the relaxation time.

Nonlinear Raman:   The Nonlinear Raman model describes a nonlinear material with third order dependency on the field. The instantaneous susceptibility follows a time resonance process similar to a Lorentz model. The model is determined by the chi3 infinity and chi3 static susceptibility coefficients and by the resonance frequency and the damping factor.

User:  The dispersion fit is based either on a constant conductivity, general 1^st order, general 2^nd order or a general n^th order model. A list of mue' mue'' values can be defined by different frequency points by pressing the Dispersion List button.

Parameter conversion frame

Note: This frame is only available for a selected magnetic gyrotropic dispersion model.

System: The Gauss or SI unit system can be selected for different input parameters of the gyromagnetic material.

Frequency: Reference frequency where the resonance line width was measured. The frequency is needed  to convert this parameter from the Gauss system into the damping factor of the SI system. See the Material Overview (HF) page for more details.