开槽无芯片RFID湿度传感器设计研究

Design of slotted chipless RFID humidity sensor

提出了一种基于RFID技术的无芯片湿度传感器标签。通过开槽蚀刻技术在覆铜FR4材料上制作缝隙散射体结构。标签结构分为两个单元:编码单元借助不同长度的缝隙组合存储ID信息;通过在缝隙表面覆盖硅纳米线沉淀层构成传感单元,用来感知湿度的变化。该方案结构简单、成本低,无任何后处理工艺。测试系统利用交叉极化的两台喇叭天线作为发射和接收天线,依据雷达电磁反向散射原理测量传输系数曲线进而获取标签的ID信息和外界湿度信息。实验测试表明在25℃温度及30%~90%的相对湿度范围内,该无芯片湿度传感器标签在215 MHz的频带范围内中心谐振频率与相对湿度呈现稳定的近似线性关系,其灵敏度超过2.9 MHz/%RH。

A chipless humidity sensor integrated with RFID is presented in the paper.The slot scatterer structure is fabricated on the copper-clad FR4 by grooving etching.The encoding unit stores the ID information by the combination of the different length slots.To make a scatterer sensitive to the humidity on the premise of low cost, the silicon nanowires are deposited on the surface of sensing unit without any post-treatment process.Based on the principle of radar electromagnetic backscattering, two horn antennas with cross polarization are utilized as the transmitting and receiving antennas so that to measure the transmission coefficient curve.The experiment results show that a stable linear relationship between the center resonant frequency and the relative humidity in the frequency band of 215 MHz is appeared at the temperature of 25 ℃ and the range of 30%~90%RH, the sensitivity of the sensor exceeds 2.9 MHz/% RH.