An encoded reconfigurable RFID strain sensor and its information fusion method

Chip-based radio frequency identification (RFID) sensor systems have been investigated for structural health monitoring applications. However, the use of chips in sensor tags has drawbacks in terms of cost, durability, and detection capability. In this paper, we propose a reconfigurable RFID-based chipless tag sensor for strain detection, which detects structural strain by observing the offset of the resonant frequency of the antenna and incorporates an encoding unit for tag identification. To realize the reconfigurability of the antenna, a PIN diode is added to control the antenna, and the frequency reconfigurability of the antenna is realized by controlling the turn on/off of the PIN diodes. The Kalman filter algorithm is used to realize the information fusion of multiple sensors to improve the sensor detection accuracy, and the background noise data enhancement is used to expand the original data samples to fuse the information of the three sensors’ data, and the relative error after fusion is reduced by about 36% compared with the relative error before fusion compared with separate measurements. The antenna was fabricated by an etching process and measured using vector network analyzer to verify the accuracy of the antenna simulation results.