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提出一种ANSYS分析Love波传感器性能的有限元方法。根据Love波传感器的特点,施加一维近似假设和周期性边界条件建立了由压电基片,金属电极和波导层组成Love波传感器的三维有限元分析模型,并在此模型分析结果基础上提取结构的特征频率。一方面运用开路和短路条件下的特征频率来计算机电耦合系数,另一方面结合微扰理论的计算得到器件的质量灵敏度。最后通过这两个参数来选取波导层厚度,使器件达到最优的性能。在不同的波导层厚度情况下,计算了SiO_2/ST-90°X石英和SiO_2/36°Y-X LiTaO_3两种结构Love波传感器结构的仿真结果,得到了这两种结构的波导层最优的厚度分别为0.11λ和0.2λ。与已报道的文献和实验的结果对比,本文所采用的方法明显优于传统的均匀层状结构理论分析的结果,通过仿真不同结构和材料参数的器件性能,有效地指导Love波传感器的设计。
A ANSYS finite element method for analyzing the performance of Love wave sensor is proposed. According to the characteristics of Love wave sensor, a three-dimensional finite element analysis model of Love wave sensor composed of piezoelectric substrate, metal electrode and waveguide layer is established by applying one-dimensional approximate assumption and periodic boundary condition. Based on the model analysis results, The characteristic frequency of the structure. On the one hand, the characteristic frequency of open circuit and short circuit is used to calculate the electromechanical coupling coefficient; on the other hand, the mass sensitivity of the device is obtained by the calculation of perturbation theory. Finally, through these two parameters to select the waveguide layer thickness, the device to achieve optimal performance. The simulation results of the structure of Love wave sensor with two structures of SiO_2 / ST-90 ° X quartz and SiO_2 / 36 ° YX LiTaO_3 were calculated under different thickness of the waveguide layer. The optimal thickness of the waveguide layer of the two structures was obtained Respectively 0.11λ and 0.2λ. Compared with the reported results of literature and experiments, the proposed method is obviously superior to the traditional theory of uniform layered structure. By simulating the performance of devices with different structures and material parameters, the proposed method can effectively guide the design of Love wave sensors.