Stepped-waveguide technique for the extraction of the electromagnetic parameters of conductor-backed absorbers

A technique to extract the electromagnetic properties of conductor-backed absorbing materials is introduced. The sample is first placed into a waveguide, completely filling its cross-section. Then a portion of the sample is fit into a reduced-step guide. The two measured reflection coefficients provide sufficient information to obtain both the complex permittivity and permeability of the sample. The usefulness of the technique may be evaluated by testing the sensitivity of the extracted material parameters to instrumentation uncertainty.