Modeling of dielectric dispersive characteristics and the step response of transmission line

In this paper, a modeling of frequency depended dielectric dispersive characteristics of transmission line and its step responses are described. A dielectric dispersive characteristic can be shown by complex relative permittivity of medium. The Debye type and the Lorenz type dispersive characteristics are investigated. The equivalent circuit representations of per unit length parameters of the transmission line are derived for these types. These equivalent circuits are exact. The time domain characteristic of this transmission line is obtained by the Fast Inverse Laplace Transform(FILT). It is understood that when the resonance frequency of dielectric medium becomes near the inverse of the step pulse risetime, the step response is distorted.