Theoretical and experimental investigation of QSH (quasi shear horizontal) acoustic waves

This paper presents a detailed theoretical and experimental investigation of quasi shear horizontal (QSH) acoustic waves in thin plates of lithium niobate. Properties that have been studied include electromechanical coupling coefficient, dispersion characteristics, temperature coefficient of delay, and influence of a biasing electric field on the wave velocity. All propagation directions in X , Y , and Z -cut plates have been investigated. The QSH wave can provide very high electromechanical coupling. Values of coupling coefficient K 2 as high as 0.36 can be obtained for waves propagating in the X direction of Y -cut lithium niobate plates. The nearly non-dispersive propagation, the large K 2 value, and the ability to propagate in contact with a liquid medium makes the QSH wave attractive for use in a variety of sensing and signal processing applications. The data presented in this paper is essential to optimize the design and performance of QSH wave devices.