双层压电板的180°畴中传播的SH型电声表面波研究

SH Type Electro-Acoustic Surface Waves in a Two-Layered Piezoelectric Plate with 180° Ferroelectric Domain Wall

本文从一般的压电方程出发,给出了在双层压电板的180°畴中传播的SH型电声表面波波解,着重讨论了两层的厚度相等时的情况,并给出了其色散关系及波场的空间分布.理论分析和实验测试均表明等厚双层压电板与铁电畴层波波导具有相似的传输特性,且更有利于低频信号的传输.

The SH type electro-acoustic surface waves in a two-layered piezoelectric plate with 180?ferroelectric domain wall are discussed. Emphasis is laid on the case where the thicknesses of the two layers are identical. Theoretical and experimental results show that in this case the surface wave is a dispersion one with its phase velocity lying between Us(the phase velocity of bulk shear wave in a nonpiezoelectric 6 mm medium)and VMI(the phase velocity of Maerfeld-Tournois wave). Its transmission characteristics are similar to those of the ferroelectric domain layer wave (FDLW), and its phase velocity is lower than that of FDLW. Compared with the waveguide of M-T wave, the waveguide of the wave studied has a higher output signal amplitude and lower loss. The two-layered piezoelectric plate is more useful for the miniaturization of SAW devices than using the waveguide of M-T wave or FDLW because it does not need any semi-infinite substrate.