On the time-domain response of havriliak-negami dielectrics

We apply a combination of asymptotic and numerical methods to study electromagnetic pulse propagation in the Havriliak-Negami permittivity model of fractional relaxation. This dielectric model contains the Cole-Cole and Cole-Davidson models as special cases. We analytically determine the impulse response at short and long distances behind the wavefront, and validate our results with numerical methods for performing inverse Laplace transforms and for directly solving the time-domain Maxwell equations in such dielectrics. We find that the time-domain response of Havriliak-Negami dielectrics is significantly different from that obtained for Debye dielectrics. This makes possible using pulse propagation measurements in TDR setups in order to determine the appropriate dielectric model, and its parameters, for the actual dielectric whose properties are being measured.