A Passive Wireless Acceleration Sensing System Based on Patch Antenna and FMCW Radar
Zhuoran Yi, Liyu Xie, Songtao Xue, Guochun Wan
Abstract
Traditional acceleration sensors use cables to transport data and batteries to supply power, which may increase failure risk, deployment inconvenience, and maintenance difficulty. This article proposes a passive and wireless acceleration sensing system, namely, a newly designed patch-antenna-based sensing node interrogated by frequency-modulated continuous-wave (FMCW) radar. The acceleration is correlated with the location of a cantilever beam, whose oscillation alters the additional capacitance of the patch antenna and consequently the resonant frequencies. The testing range can be adjusted by changing the material and dimensions of the cantilever beam, which is designed up to ±110 m/s 2 with a sampling rate of 500 Hz to meet the requirements of different conditions. The working mechanism of the sensing system is analyzed theoretically and then verified by the simulation in COMSOL Multiphysics. Then, an experiment is carried out to evaluate the performance of the sensing system. Both the resonant frequency and remaining power can be utilized to extract the acceleration response, and results show a good fit with the actual response (i.e., an average error of 4.5%). Empowered by FMCW Radar, the passive accelerometer may have great potential in identifying structure strain mode, impedance-based detection of bolt loosening, automation in construction, etc.