Metamaterial inspired contactless angular displacement sensor with wide dynamic range and bandwidth

Abstract

A new design approach of microwave rotation sensor using separated ring of double split ring resonator (DSRR) is presented in this work. The proposed sensor provides the contactless determination of angular displacement by investigating the shift in resonant frequency. The novel design configuration helps to obtain the wide dynamic range, resolution, linearity and sensitivity. In this work two rings of DSRR has been separated vertically to attach them one at stator and other one at rotor to perform the contact less wide range rotation measurement using the asymmetry of rectangular SRR ring. Rotation of inner ring attached on the rotor results into change in its coupling with the outer ring present at the stator. This actually changes the overall capacitance of the sensing region thereby changing the resonant frequency of the sensor. The designed sensor dimensions are optimized in order to get the improved sensitivity and linearity in the wide dynamic range of 0 to 120°. Maximum achievable frequency shift using the proposed sensor is found to be nearly 19 MHz/°. Moreover, the designed sensor can cover the maximum angular displacement range of nearly 5 mm with 2 GHz bandwidth using only the single sensor arrangement, unlikely the multi cell SRR arrangement where the maximum displacement coverage is ~ 1 mm with 0.5 GHz bandwidth.