Microwave Rotation Sensor Based on Reflection Phase in Transmission Lines Terminated With Lumped Resonators
Zahra Mehrjoo, Amir Ebrahimi, Grzegorz Beziuk, Ferran Martı́n, Kamran Ghorbani
Abstract
A phase variation-based rotation sensor is presented in this article. The sensor is realized using a coplanar waveguide (CPW) terminated with a stepped impedance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit {LC}$ </tex-math></inline-formula> resonator. A circular dielectric slab is rotating above the resonator. Rotation of the slab modifies the overall capacitance and, thus, the input impedance of the resonator. This, in turn, modifies the phase of the reflection coefficient, which is translated to the rotation angle. The sensor’s linearity is eventually enhanced by tapering the width of the capacitive metallic patch along the rotation direction. The operation and sensing performance are studied in detail, using a circuit-based analysis and electromagnetic (EM) simulations. The designed sensor is capable of detecting the direction of rotation. A sensor prototype is fabricated and experimentally measured to prove the developed design and analysis procedure.