Kuznetsova I E, Zaitsev B D, Borodina I A, Teplyh A A, Shurygin V V, Joshi S G
Institute of Radio Engineering and Electronics, Saratov 410019, Russia.
Ultrasonics. 2004 Apr;42(1-9):179-82. doi: 10.1016/j.ultras.2004.01.006.
This paper presents theoretical investigation of higher order acoustic plate waves propagating in single crystals of lithium niobate. The dependencies of wave velocity and electromechanical coupling coefficient of antisymmetric, symmetric, and shear horizontal modes on the parameter hf (h=plate thickness, f=operating frequency) are calculated as a function of propagation direction on X-, Y-, and Z-cut lithium niobate plates. It is found that several modes can provide values of K2 that are much greater than can be obtained with surface acoustic waves (SAWs). For example, K2 as high as 0.26 and 0.38 can be obtained from SH1 and A2 modes, respectively. This compares with a maximum value of K2=0.055 for SAWs. It is further shown that there are several crystal cut and propagation directions that can allow efficient excitation and detection of a single mode with minimal interference due to other modes.
本文对在铌酸锂单晶中传播的高阶声板波进行了理论研究。计算了反对称、对称和水平剪切模式的波速和机电耦合系数与参数hf（h = 板厚，f = 工作频率）的依赖关系，该依赖关系是关于X切、Y切和Z切铌酸锂板上传播方向的函数。结果发现，几种模式能够提供比表面声波（SAW）所能获得的值大得多的K²值。例如，从SH1和A2模式分别可获得高达0.26和0.38的K²值。相比之下，SAW的K²最大值为0.055。进一步表明，存在几种晶体切割方式和传播方向，能够在受到其他模式的干扰最小的情况下，实现对单一模式的高效激发和检测。
