基于微波网络理论,提出了一种基于变绝缘层的同轴光子带隙晶体应变传感器的设计方法。给出了同轴光子带隙晶体传感器的结构形式,推导了传感器带隙极值频率与晶体电长度之间的关系。根据给定监测频点设计了传感器的几何尺寸及材料参数,计算了传感器的S参数,计算结果与仿真结果相吻合。分析了提高该传感器灵敏度和品质因数的方法,并搭建了实验测试平台。实验结果表明:当应变量由0με提高至10 000με时,极值频率由2.450GHz移至2.432GHz,频移量为18 MHz,灵敏度为1.8kHz/με。得到的实验结果与仿真结果相吻合,验证了本文所提出的基于变绝缘层的同轴光子带隙晶体应变传感器设计方法的可行性和有效性。该传感器可满足不同灵敏度需求下对应变的实时监测。
According to microwave network theory,a coaxial photonic band gap crystal strain sensor was proposed based on a variable insulating layer.The model of the coaxial photonic band-gap crystal sensor was provided,and the relationship between the peak frequency of band gap and the electric length of the crystal was deduced.The structural size and the material parameters of the coaxial photonic band gap crystal sensor under a certain demand were designed.The Sparameters were calculated,and they are well coincided with that from a simulation.The method for improving the sensitivity and quality factor of the sensor was analyzed and an experimental platform was set up.The experimental result shows that when the strain changes from 0μεto 10 000με,the peak frequency of the band gap is changed from 2.450 GHz to 2.432 GHz,in which the frequency shift is 18 MHz,and the sensitivity is 1.8kHz/με.The simulation results coincide with the experimental one,and validate the feasibility of the designing method of the strain sensor.