Separating strain sensor based on dual-resonant circular patch antenna with chipless RFID tag

Abstract

In the field of structural health detection, since the sensor needs to be directly bonded to the measured object, it is difficult to stably transmit the RFID information and realize the passive wireless structure strain detection. To circumvent these difficulties, this paper innovatively proposes a dual-resonant circular microstrip patch antenna (CMPA) sensor with chipless RFID tag. The information of the RFID tag can be changed that allows the sensor to be deployed on a large scale. The separating sensor includes chipless RFID tag layer and dual-resonant CMPA layer, which can simultaneously reflect RFID tag information and strain information.The design of separated layers can minimize the resonant frequency shift of ID tags when stress is implemented on CMPA strain part. Current distribution analysis and equivalent circuit are used to study the strain size and direction. Experiments show that the offset of the resonant frequency of the sensor antenna has linear relationship with the lateral and longitudinal strains. The correlation coefficients are 0.9284 and 0.9235 respectively, and the sensitivity coefficient of the lateral and longitudinal strain is 528 MHz ϵ −1 and 384 MHz ϵ −1. At the same time, the readability of the RFID tag information is maintained.