Design of a high-gain strain sensor for monitoring structural health based on passive UHF RFID

Structural health monitoring (SHM) refers to the implementation of damage detection and identification of engineering structures. The damage which we have described includes changes in the properties of the material or the geometrical properties of the system. Traditionally, common sensors are used in the SHM although significant improvements have been made on damage monitoring techniques by using advanced smart sensors, but connecting line and power supply remains a significant challenge to the practical implementation of these technologies. In the article, we propose a UHF rectangular patch antenna which is wireless and passive comparing with the traditional methods. Through good linear polarization, we can get an ideal gain which can allow a larger measurement distance. As the size of antenna changes, the resonant frequency will transform accordingly. When it is used in the SHM, a great convenience in the field can be obtained.