一种基于无源RFID的裂缝传感器设计

A Novel Design of Crack Sensor Based on Passive RFID

基于无源RFID原理,提出了一种安全可靠、结构简单、价格低廉的新型裂缝标签传感器。该标签由两个嵌套的环形缝隙天线、二倍压整流电路、二次谐波带阻滤波器和发光报警电路组成,工作频率为f0=2.45 GHz,并使用0.254 mm厚超薄型高频覆铜板加工制作完成。当裂缝出现时,带阻滤波器与传感器标签断开连接,标签中的二次谐波信号通过缝隙天线发送到接收端实现远距离报警,同时标签中的直流信号给发光报警电路供电实现近距离的位置报警。实验结果表明,当有效发射功率为35 dBm时,传感器标签的预警距离可达7 m以上,发光定位的正常工作距离超过0.8 m。

Based on the principle of passive RFID,a new type of crack sensor tag with safety,reliability,simple structure and low cost is proposed in this paper. The tag consists of two nested loop-slot antennas,a double-voltage rectifier circuit,a second harmonic band-stop filter,and a light-emitting alarm circuit. The working frequency f0is set to be 2.45 GHz,and all the circuit parts are fabricated on a ultra-thin high frequency copper laminate with the thickness of 0.254 mm. In the case of cracks,the band-stop filter is separated from the sensor tag,and then the second harmonic signal can be sent to the receiver by the slot antenna to achieve a remote alarm. At the same time,the DC signal in the tag can further power the light-emitting alarm circuit to realize close-range position alarm. The experimental results show that the long-range working distance of the sensor tag can reach to 7 m,and the normal working range of light-emitting positioning is larger than 0.8 m if the effective transmission power is chosen as 35 dBm.