Extracting μr and εr of solids from one-port phasor network analyzer measurements

A method for simultaneously and rapidly extracting permittivity, ε, and permeability, μ, of nonmetallic solids over a wide range of frequencies, based on one-port reflection measurements made by an automatic network analyzer (ANA), is described. Reflection measurements are taken of a short, an offset short-circuited air line of length l , and two short-circuited samples of lengths land nl , where n is any integer >1. The information contained in these four measurements is sufficient to extract ε and μ without recourse to any a priori knowledge of the waveguide´s cross section, dispersion, or loss. This method is particularly convenient for measuring ε and μ at temperatures significantly different from ambient and in waveguide cross sections whose dispersion and loss are not well known. The presence of higher order modes and of sample inhomogeneities can be detected from an additional measurement of an offset short-circuited air line of length nl. Measurements at Ka-band on polystyrene agree with those of other investigators. A number of practical considerations for successfully implementing the method discussed above, relating to sample length, time-domain gating, mode suppression, and sample fabrication, are discussed