压电晶体本征声表面波倒速度曲线的计算

Calculation of Reciprocal Velocity Curves of Intrinsic Surface Acoustic Wave in Piezoelectric Crystal

为在设计表面波器件时选择基底的最佳切割方向,提出压电修正劲度系数的概念,并计算了石英和铌酸锂晶体的压电修正劲度系数.从晶体的性能方程出发,推导了本征表面波声学基本方程和表面波力学边界条件方程,使用新的计算声表面波速度的循环迭代法,分别对石英和铌酸锂2种晶体,在3个坐标平面内,计算非压电修正及压电修正的本征声表面波倒速度曲线.研究结果表明,压电效应加快了声表面波速度,晶体的表面波声学性质与其点群对称性之间有内在的联系.

In order to select optimum cut direction of the substrates in designing devices,a concept of piezoelectric-modified stiffness coefficients is put forward and it is calculated for the quartz and LN crystal. Intrinsic SAW basic equations and mechanics boundary conditions equations are deduced from character equation of crystal. Using a new circular iterative method,non piezoelectric-modified and piezoelectric-modified intrinsic SAW reciprocal velocity curves are calculated in three coordinate planes for the quartz and LN crystals. Research results indicate that intrinsic SAW velocities are quickened due to the piezoelectric effect. There is internal relationship between the SAW properties and point group symmetries of the crystal.