Frequency-Dependent Material Properties

The properties of some materials vary with the frequency of the field excitation. Frequency dependence is often linear within a certain range and is constant outside the frequency range, as shown in the following figure,

where

• epsr_lower is the relative permittivity of a material below the frequency range 20 - 50 GHz.
• epsr_upper is the relative permittivity of a material above the frequency range 20 - 50 GHz.
• f_lower is the lower frequency, below which the material property is constant.
• f_upper is the upper frequency, above which the material property is constant.

In general, to account for this variance within a given frequency range, use the Piecewise Linear Material Input window window to specify a property’s values at frequencies below and above the frequency range. Based on these values, Ansys Desktop automatically creates a linear dataset that specifies the property’s values at the chosen frequencies during solution generation. This dataset can be modified with additional points if chosen.