A dielectric resonator inspired displacement sensor

Abstract

Preliminary experimental studies on a cylindrical dielectric resonator (DR) excited by a microstrip line are presented, with the purpose of proposing the structure for sensing small displacements. A 50 Ω microstrip line excites a DR of dielectric constant 24, diameter 19.43 mm, and height 7.3 mm. The arrangement is placed in the open environment so that the HEM11δ mode is excited as the fundamental mode. Optimum impedance matching occurs at a resonant frequency of 3.4 GHz with a reflection coefficient of −40 dB. Studies on the sensitivity of resonant frequency to offsets in the feed position are performed, and 28.5 MHz/mm is measured in the input range of −1 to 6 mm. This feature which is undesired in conventional applications may be used for displacement sensing applications.