Performance analysis of an open ended coaxial resonator based displacement sensor

In this paper, an open ended coaxial resonator based displacement sensor is presented. The developed device is capable of determining the xy-plane displacement in a contactless way. The sensor system is constructed from a dielectric wedge, a coaxial resonator, as well as two ISM band Radio modules. The resonance frequency and quality factor of the cavity change when the dielectric target moves with respect to the open end of the resonator. Measuring the transmission of the resonator, a resonance curves can be created which clearly define the position of the target. The perturbation based operating principle of the sensor has been tested using loads made of teflon and rogers. Addition to high accuracy and range, the easy and cheap evaluation of the results make the presented sensor system particularly interesting for industrial applications.