Measurements of the Permittivity of Materials Using the Double-Ridged Waveguide

A broadband method for measuring the complex permittivity of materials for the microwave range is proposed. The double-ridged waveguide is offered to use as a measuring cell. The developed method makes it possible to increase the accuracy of determining the complex permittivity of materials by placing the sample between the waveguide ridges at the maximum of the electric field intensity of the fundamental wave. Electrodynamic characteristics of the double-ridged waveguide with a dielectric sample are presented: cutoff frequencies, propagation constants, and the structure of the fundamental hybrid wave at the operating frequency. The measurement results of the complex permittivity of a Teflon sample are shown.