基于U形谐振器的无源裂缝传感器

Passive crack sensor based on a U-shaped resonator

针对传统裂缝传感器需要电源供应才能正常工作的缺陷,本文提出了一种基于无应力组合式贴片天线的无源裂缝传感器设计。利用U形谐振器实现裂缝传感,改变传感器内部谐振单元的谐振频率。通过观测回波信号的幅度和相位提取传感器的谐振频率,进而实现对裂缝的监测。基于天线理论建立了传感器的等效电路模型并推导谐振频率,研究裂缝宽度对传感器谐振频率的影响规律。进一步在三维电磁仿真软件CST中对传感器进行了数值模拟,并且通过试验研究了裂缝拓展对谐振频率的影响。研究表明:随着裂缝的扩展,传感器的谐振频率增加,且裂缝宽度与谐振频率之间具有较好的线性关系。

To solve the defect where a normally working traditional crack sensor requires a power supply,a passive crack sensor design based on an unstressed combined patch antenna is proposed in this paper,which utilizes a U-shaped resonator to realize crack sensing and further change the resonant frequency of the resonant unit inside the sensor.The resonant frequency of the sensor can be extracted by observing the amplitude and phase of the echo signals to realize monitoring of cracks.Based on the theory of antenna,an equivalent circuit model of the sensor was established and its resonant frequency was derived for the study of the effects of the crack width on the resonant frequency of the sensor.Furthermore,numerical simulations were conducted for sensors in the three-dimensional electromagnetic simulation software CST,and the influence of crack expansion on the resonant frequency was studied through experiments.Both simulation and experimental results show that the resonant frequency of the sensor increases with the crack expansion and that there is a good linear relationship between the crack width and the resonant frequency.