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

Jie Zou; Ventsislav Yantchev; Filip Iliev; Victor Plessky; Sohrab Samadian; Robert B Hammond; Patrick J Turner

doi:10.1109/TUFFC.2019.2944302

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

IEEE Trans Ultrason Ferroelectr Freq Control. 2020 Feb;67(2):374-386. doi: 10.1109/TUFFC.2019.2944302. Epub 2019 Sep 27.

Authors

Jie Zou, Ventsislav Yantchev, Filip Iliev, Victor Plessky, Sohrab Samadian, Robert B Hammond, Patrick J Turner

PMID: 31567078
DOI: 10.1109/TUFFC.2019.2944302

Abstract

This study lays a foundation for the design of the SH₀ plate acoustic wave (PAW) resonators based on LiNbO₃ plate, and are applicable to the ultra-wideband filters and next-generation tunable filters. The coupling coefficient ( k² ) of SH₀ mode is optimized to as high as 55% and wideband spurious are well controlled by analyzing the propagation characteristics of plate modes in LiNbO₃. The SH₀ 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.