双极化无芯片RFID金属裂纹传感器

为检测金属结构中裂纹的宽度及方向,提高检测的灵敏度和可靠性,设计了一种基于频率信号的双极化无芯片RFID传感器。在2.2~6.2 GHz频率范围内进行四频带分段设计,传感器为圆盘及双模圆盘多微带谐振器结构,利用HFSS软件对传感器进行结构优化与性能仿真。结果表明,传感器在x极化和y极化方向激励下,分别产生两组四位谐振。金属裂纹的方向根据谐振频率偏移方向判断,两种极化方式共产生八位谐振偏移信息供判定,可实现对0°、45°、90°、135°方向裂纹的准确识别;对各方向上裂纹宽度与传感器谐振频率偏移量进行拟合,两者间呈现良好的线性关系,且通过极化复用大幅提高了传感器的灵敏度,分辨率可达亚毫米级,在各个方向上灵敏度分别为40.71 MHz/0.1 mm、11.28 MHz/0.1 mm、26.04 MHz/0.1 mm、15.19 MHz/0.1 mm。制作了传感器实物并进行实验测试。设计的RFID传感器具有无源、低成本、灵敏度高的特点,在结构健康监测中具有应用潜力。

Dual-Polarization Chipless RFID Sensor for Metal Crack

In order to detect the width and direction of cracks in metal structures, and improve the sensitivity and reliability of detection, a dual-polarization chipless RFID sensor based on frequency signals is designed. The sensor is a disc and dual-mode disc multi-microstrip resonator structure. The quad-band segment design is performed in the frequency range of 2.2-6.2 GHz. The structure optimization and performance simulation of the sensor are performed using HFSS software. The results show that the sensor generates two sets of four-position resonances when excited in the x and y polarization directions. The direction of the metal crack is judged according to the direction of the resonance frequency shift. Two polarization modes generate a total of eight bits of resonance shift information for determination, which can accurately identify cracks in the directions of 0°, 45°, 90°, and 135°. The crack width in the direction is fitted to the resonance frequency offset of the sensor, and the two have a good linear relationship, and the sensitivity of the sensor is greatly improved through polarization multiplexing. The resolution can reach sub-millimeter level, and the sensitivity in all directions is 40.71 MHz/0.1 mm, 11.28 MHz/0.1 mm, 26.04 MHz/0.1 mm, 15.19 MHz/0.1 mm respectively. The RFID sensor designed in this paper has the characteristics of passive, low cost and high sensitivity, and has potential for application in structural health monitoring.