Thickness-Independent Complex Permittivity Determination of Partially Filled Thin Dielectric Materials Into Rectangular Waveguides

A microwave method has been proposed for accurate complex permittivity measurement of thin dielectric materials partially fllling the waveguide. The method employs propagation constant measurements at two locations of the sample inside its holder. It increases the accuracy of permittivity measurements of similar methods in the literature since it utilizes the measurements of the distances between the inner waveguide walls and sample lateral surfaces instead of directly measuring the sample thickness. It has been validated by comparing the measured complex permittivity of a thin Plexiglas sample by the proposed method with that of the method in the literature.