多叉指Rayleigh波器件的建模及特性研究

Study on Modeling and Properties of Multi-interdigital Rayleigh Wave Device

针对目前改变Rayleigh波器件中波的传播方向和强度较复杂的问题,提出了一种多叉指Rayleigh波器件结构和三维建模方案。该三维建模方案用有限元分析法去逼近实际器件的压电基片和叉指换能器等真实器件结构和尺寸。选取压电基片材料为128°YX-LiNbO3、叉指换能器为Al电极,分别对叉指换能器数目为4、6、8的多叉指Rayleigh波器件进行三维模型实验,验证了该器件的可行性。实验结果表明,多叉指Rayleigh波器件可以在不同角度激发Rayleigh波,该波只有x、y方向的质点位移分量,且质点的最大位移主要集中在器件表面的中心位置。此外,器件的模态频率和质点最大位移随着叉指换能器数目的增加而增大,由此产生的Rayleigh波强度和器件的混合性能也会增强。

Aiming at the complex problem of changing the direction and intensity of wave propagation in the Rayleigh wave devices, a multi-interdigital Rayleigh wave device structure and a three-dimensional modeling scheme are proposed in this paper. The three-dimensional modeling scheme uses finite element analysis to approximate the real device structure and size such as piezoelectric substrate and interdigital transducer. The chosen piezoelectric substrate material is 128° YX -LiNbO 3, and the interdigital transducer is an Al electrode. The three-dimensional model experiment is carried out on the multi-interdigital Rayleigh wave device with the number of interdigital transducers of 4, 6, and 8 respectively, and the feasibility of the device is verified. The experimental results show that the multi-interdigital Rayleigh wave device can generate Rayleigh waves at different angles. The generated wave only has the particle displacement components in the x and y directions, and the maximum displacement of the particles is mainly concentrated on the center of the device surface. In addition, the modal frequency and maximum displacement of the device will increase with the increase of number of interdigital transducers. Therefore, the generated Rayleigh wave intensity and the mixing performance of the device are also enhanced.