LITHIUM NIOBATE THIN FILM BASED A3 MODE RESONATORS WITH HIGH EFFECTIVE COUPLING COEFFICIENT OF 6.72%

In this paper, 600nm Z-cut lithium niobate (LiNbO3) thin film based third-order antisymmetric (A3) mode resonators with different geometries has been investigated. Through a series of experiments, it has been found for the first time that effective electromechanical coupling coefficient (K-eff(2)) is influenced by the gap between electrodes (Ge), and K-eff(2) decreases with the increase of Ge when electrode pitch (P) higher than Sum. Finally, a A3 mode resonator with a high K-eff(2) of 6.72% is obtained. This K-eff(2) is the highest reported value in similar acoustic resonators working about 9 GHz and will be beneficial to the construction of X-band filters.