Passive wireless strain and crack sensing using a RFID-based patch antenna

Abstract As an important parameter of structural health monitoring, strain can be an important indicator for stress concentration and crack development. And stress/crack can effectively evaluate the health status of the structure. Micro-strip antenna strain sensing technology, as a passive wireless detection technology, is of great significance to the health monitoring of high-end equipment bearing structures. In this work, the UHF (Ultra High Frequency) RFID (Radio Frequency Identification) technology is combined with the micro-strip antenna technology. And the micro-strip antenna is used as the tag antenna to receive the energy emitted by the RFID reader and activate the tag chip of the RFID. Then the signal modulation technology is used to eliminate the noise interference in the environment, and the resonant frequency of the antenna changes with the strain/crack information is returned to the reader to realize the passive wireless strain and crack detection. Through the experiment, it proves that under different strain/crack states, the resonant frequency of the RFID-based antenna sensor decreases with the increase of strain or the increase of the depth of the crack.