Flexible Lamb Wave Resonators Based on Lithium Niobate Thin Film

This paper presents mechanically flexible lamb wave resonators (LWRs) based on single-crystal lithium niobate (LN) thin film. In contrast to conventional LWRs on silicon substrate, flexible LWRs are fabricated on polyimide (PI) substrate. The flexible resonator is realized by our FlexMEMS technology, which endows MEMS devices with excellent mechanical flexibility and electrical performance. The resonator is driven by lateral field excitation, and exhibits a resonance frequency of 378.2 MHz, $Q$ of 770, Kt 2 of 11.2%, and a parallel-to-series resonance impedance ratio of 552. The resonator also demonstrates its mechanical stability under a series of bending tests. The electrical performance of the LN-based flexible LWR is superior to that of the AIN-based flexible LWR demonstrated in our previous work. The high performance flexible LWR extends the applications to a broad range of flexible electronics, such as flexible sensors, filters and oscillators.