Phase Variation Reflective-Mode Displacement Sensor Using a CPW Loaded with Dumbbell-Shaped Resonator
Zahra Mehrjoo, Amir Ebrahimi, Kamran Ghorbani
Abstract
A high sensitivity reflective mode displacement sensor is designed in this paper based on the phase variation. The phase variation due to the displacement is measured in a single frequency, resulting in a simple measurement setup. The sensor is designed using a Coplanar Waveguide (CPW) terminated with a capacitive patch. A dumbbell-shaped resonator is etched at the back of the substrate, where displacing the resonator above the capacitive patch modifies the overall capacitance, resulting in phase variation in S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> . The sensing principle is analyzed in detail, using an accurate circuit model and full-wave electromagnetic simulations. The proposed sensing method is capable of detecting the displacement direction.