Combination of Tetragonal Crystals with LiTaO3 Thin Plate for Transverse Resonance Suppression of Surface Acoustic Wave Devices

This paper discusses combination of tetragonal crystals with LiTaO 3 (LT) thin plate for complete transverse resonance suppression of surface acoustic wave devices without k 2 deterioration by manipulating the slowness shape. Besides, better lateral energy confinement is achieved as well by the use of double busbar structure. First, the mechanism of slowness shape manipulation by combining tetragonal crystals is studied. By comparison, YZ-lithium tetraborate (LBO) shows better performance than 69°Y90°X quartz. Then numerical simulations are carried out using periodic three-dimensional finite method assisted by hierarchical cascading technique, and the effectiveness of transverse mode suppression by flattening the slowness shape is revealed. And the possibility to realize temperature compensation is discussed owing to the unique material property of LBO. Moreover, the capability of other tetragonal crystals for slowness manipulation are compared, and LBO is the best choice among these tetragonal crystals.