Ultra-Large-Coupling and Spurious-Free SH0 Plate Acoustic Wave Resonators Based on Thin LiNbO3

This study lays a foundation for the design of the SH 0 plate acoustic wave (PAW) resonators based on LiNbO 3 plate, and are applicable to the ultra-wideband filters and next-generation tunable filters. The coupling coefficient (k 2 ) of SH 0 mode is optimized to as high as 55% and wideband spurious are well controlled by analyzing the propagation characteristics of plate modes in LiNbO 3 . The SH 0 mode is demonstrated to be slowly dispersive and features the superiority of interdigital transducer (IDT)-defining frequency over most other plate modes. On the device level, the transducer types and electrode materials are investigated and compared. In addition, for edge-reflected SH0 resonators, stopband dispersion analysis is provided and the longitudinal ripples are suppressed. For edge-reflected SH0 resonators, a novel perfect edge reflector is proposed with elimination of longitudinal spurious ripples.