A modified cavity perturbation technique for measurement of the dielectric constant of high permittivity materials

Abstract

A technique for complex permittivity measurements in the microwave region is presented. In this method, a cylindrical cavity is loaded along its central axis with a concentric lossy material. The resonance condition of the structure is obtained from the exact field theory solution and is coupled to the experimental measurements of resonant frequency and Q-factor to provide E 1 and E values. Accurate results are obtained using relatively large samples even for high permittivity or very lossy materials, provided the resonance mode selected has an electric field minimum along the central axis of the cavity. An additional advantage of the formulation is that it does not require any prior calibration with known standards. © Springer-Verlag Berlin Heidelberg 2006.