Dual-probe lowloss material extraction technique

A dual-probe rectangular waveguide material-parameter extraction technique capable of accommodating lowloss samples is presented. The technique´s ability to easily measure reflection and transmission (R/T) coefficients necessary for simultaneous extraction of permittivity and permeability over all frequencies is discussed. Love´s equivalence principle is used to create a system of coupled magnetic field integral equations (MFIEs) for the theoretical R/T coefficients which are subsequently solved using the Method of Moments (MoM). The material parameters are extracted via least squares by minimizing the magnitude of the difference of the theoretical and measured R/T coefficients. It is shown how the signal processing concept of time-domain gating can be utilized to mitigate edge diffraction effects of the finite waveguide flange. Material parameter extraction results, based on a single waveguide mode expansion, for various lossy and lowloss materials are provided to verify the technique.