声子晶体点缺陷模式质量传感的位置解耦方法

Position Decoupling Method of Mass Sensor Based on Point Defect Modes in Phononic Crystal

声子晶体点缺陷微小的振动质量和高品质因数(Q)使之用于质量传感时可以提高灵敏度和分辨率,但其灵敏度受被测物位置影响。制作硅基点缺陷结构,建立了计算缺陷模式的质量灵敏度的弹簧-振子模型。通过实验验证,实验中最高灵敏度为9.1Hz/ng。提出了一种利用多模式的灵敏度分布差异对质量和位置进行解耦的算法,并予以仿真验证。采用3种和8种模式测量质量的相对误差分别为2.6%和0.43%。

The tiny resonant mass and high Qperformance of phononic crystal（PC）point defect make it an excellent candidate for high sensitivity and resolution mass sensors,but its mass sensitivity is highly dependent on the mass positions.In this paper,we fabricate the silicon-based PC point defect structures and establish a spring-mass model to evaluate the mass sensitivities of the defect modes.The experimental results agree well with the model and the highest mass sensitivity of 9.1Hz/ng is obtained.Furthermore,we propose a method utilizing the diverse sensitivity distributions of the defect modes to decouple the mass and position simultaneously and demonstrate it in simulation.The results show that the relative errors are 2.6% and 0.43% respectively with 3and 8 modes for mass measurement.