Non-Destructive Measurement of Complex Permittivity for Dielectric Slabs

Abstract

A method has been developed for a precise non-destructive measurement of the dielectric constant and losses of slab-like samples, such as microstrip substrates for instance. The test setup basically consists of an open-ended rectangular waveguide whose flange is placed in contact with one side of the dielectric material, the other one being backed by a metal plate. The measured amplitude and phase of the reflection coefficient with respect to a short-circuit in the aperture plane are related to the real and imaginary parts of the permittivity by means of computer generated charts.