IIR filter implementation of dispersive medium using Z-transform

The Z-transform method for modeling the dispersive media is analyzed mathematically. The most complicated part of modeling of this medium is to find a relationship between the flux densities and the field intensities. Because of the simplicity of the finite difference in time-domain, this relationship can be looked upon as a digital filtering issue. In this paper, the Z-transform is used to incorporate the dispersive medium constitutive relations into the frequency algorithms. An IIR filter structure is designed to show the non-linear behavior of the frequency dependent permeability of materials using properties of the Z-transform.