Abstract
This work presents a set of high performance longitudinal leaky surface acoustic wave (LLSAW) resonators based on lithium niobate LN/SiO2/Sapphire (LNOS) characterized by a larger phase velocity. The LLSAW resonators on the proposed LNOS platform results a remarkable 9-fold improvement the figure of merit compared to the identical devices on LN/SiO2/Silicon platform. As a result, the LLSAW resonators demonstrated both a high-quality factor (Qmax > 1010) and a large electromechanical coupling coefficient (keff2 > 14.3%) which yielding a figure-of-merit (FoM = keff2 · Qmax) exceeding 145 for the first time in L-band region. These findings showcase a highly competitive performance compared to state-of-art thin film LLSAW resonators.