A low-cost reflection mode operated microwave resonator sensor for angular displacement detection

A low-cost microwave resonator sensor for angular displacement detection is proposed. The sensor uses a strip-loaded dielectric resonator (SLDR) as the key element. The sensor operates in the reflection mode, i.e. by producing a variation in the reflection coefficient (S11) according to the angular position of the SLDR relative to a microstrip transmission line. The primary advantage of the proposed strategy is its fixed-frequency operation enabling the S11 measurement with a low-cost reflectometer, thereby avoiding the costly vector network analyzer (VNA). Design modelling and initial analysis of the sensor are performed with ANSYS HFSS software. To demonstrate proof of concept, a sensor prototype is fabricated and experimentally characterized with a custom-made reflectometer. Results are compared against VNA-based measurements to be in decent agreement. The proposed sensor exhibits 0.43 dB/0 sensitivity over the dynamic range of 00–900.