High Frequency Vibration Analysis Of LiTaO₃ Pizoelectric Resonators Excited By Lateral Electric Fields

The lateral-field-excitation?LFE?based quartz bulk acoustic wave devices are not applied widely because the low piezoelectric coupling factors and the limited sensitivities.Lithium Tantalate?LiTaO₃?crystals are with high piezoelectric coupling factors and are suitable for being applied in LFE bulk acoustic wave devices.However,for LiTaO₃ LFE devices,the electric field and displacement distributions are more complicated than quartz LFE devices because of high piezoelectric coupling factors,and the vibration characteristics are not clear,which needs further study.In this paper,for the?yxl?-90°LiTaO₃ piezoelectric bulk acoustic wave device,the high-frequency vibration are analyzed by the theoretical and FEM methods.The theoretical analysis method of?yxl?-90°LiTaO₃ LFE piezoelectric bulk acoustic wave device excited are presented,the electrode and crystal plate cutoff frequency range of the device are determined,the optimal parameter design criteria for the device are given,and the influence of the different mass ratio values R of electrodes,gap values,and electrode width values b₁ on the vibration of the device are analyzed.For FEM,a model of the resonator of the?yxl?-90°LiTaO₃ crystal excited by the lateral electric field is established by COMSOL Multiphysics.For the symmetrical structure,the influence of mass ratio R,gap a,electrode width b on vibration characteristics are analyzed.For the asymmetric structure,the influence of electrode/crystal plate mass ratio R_R and the electrode width b₁ on vibration characteristics are mainly analyzed.In this study,a theoretical analysis method of LiTaO3 piezoelectric bulk acoustic wave device excited by lateral field is presented,the finite element method is used to verify the theoretical analysis,which can provide theoretical basis for the practical application of lateral field excited LiTaO₃ piezoelectric bulk acoustic waves.