Design of a Wideband System for Measuring Dielectric Properties

A dielectric object placed in the near-field region of an antenna produces a scattered field, which alters the input impedance of the antenna. This property can be used to measure the electric parameters of dielectric materials. A wideband system for measuring the dielectric properties in the frequency range from 1.1 to 3.5 GHz is designed and prototyped. The system consists of a wideband directional antenna, a wideband radio frequency circuit, and a data processing unit and has been tested by using different dielectric samples across the frequency band, and good measurement results have been obtained.