Flexible lamb wave resonators with high figure of merit

This paper presents a 429 MHz flexible Lamb wave resonator based on lithium niobate thin films with a high figure of merit (FoM) of 205, which is about 10 times higher than the FoM of the flexible resonator presented in our previous work. The measured corresponding quality factor (Q) and electromechanical coupling coefficient (K-t(2)) are 1268 and 16.2%, respectively. The resonant frequency, Q, and K-t(2) of the flexible resonator show maximum changes of only 0.11%, 0.37%, and 0.31%, respectively, under a repeated mechanical bending condition up to 10 000 times at a bending radius of 3 mm. We also found that FlexMEMS technology we proposed not only endows Lamb wave resonators with mechanical flexibility but also improves FoM by similar to 180% compared to their counterpart, conventional Lamb wave resonators on rigid silicon substrates. The flexible resonators with much improved FoM will find applications as low-power radio frequency key components in emerging applications, especially Internet of Things. Published under license by AIP Publishing.