A novel passive RFID sensor for crack monitoring of metallic structures

Structural Health Monitoring (SHM) is essential for maintaining the safety and integrity of many large-scale buildings and infrastructure. In the scope of the Internet of Things (IoT), Radio Frequency Identification (RFID) introduces an innovative approach to SHM. This investigation presents a cost-effective passive RFID crack sensor solution tailored for IoT applications. An RFID tag sensor with a Planar Inverted-F Antenna (PIFA) structure specifically is designed to detect and characterize surface cracks on metallic structures. In addition, a low-cost detection method optimized for large-scale mechanical systems is proposed. Traditional SHM techniques often face challenges in adapting to IoT environments due to their complex measurement processes and a high cost. The RFID tag sensor, featuring anti-metal properties, compact size, high data capacity, and high sensitivity, could potentially overcome these challenges. To enhance the sensing precision, a Defected Ground Structure (DGS) is integrated into the sensor design, which allows the sensor to accurately determine the direction of cracks. The sensing data is collected and transmitted to a host PC using a commercial RFID reader, and Principal Component Analysis (PCA) algorithm is employed to improve the detection accuracy. The proposed RFID sensor solution provides an efficient solution for safety assessment and damage detection in large infrastructure structures.