Chipless RFID Sensors for Crack Angle and Direction Detection

A novel sensor design for chipless RFID is proposed to detect the width and direction of metal cracks. The sensor is a circular microstrip patch antenna and a multi-arc patch antenna structure. The operating frequency band of the sensor is 2.5~4.5 GHz. 5 resonant frequencies are generated in the resulting RCS spectrum through simulation experiments, and the first four resonant frequencies are encoded and designed. The metal crack direction and width are judged by the frequency offset degree and coding information, which can realize the detection of 0°, 40°, 90°, 120° and 150° cracks. The sensitivity is up to 196.6 MHz/mm.The proposed sensor adopts passive design with low cost and has good application prospect.