Lateral-field-excitation properties of LiNbO3 single crystal

LiNbO₃ has been found attractive for lateral field excitation(LFE) applications due to its high piezoelectric coupling. In thispaper, bulk acoustic wave propagation properties for LiNbO₃single crystal excited by a lateral electric field have beeninvestigated using the extended Christoffel--Bechmann method. It isfound that the LFE piezoelectric coupling factor for c modereaches its maximum value of 95.46% when ψ = 0° forboth (yxl)-58° and (yxwl)± 60°/58° LiNbO₃.The acoustic wave phase velocity of c mode TSM (thickness shearmode) changes from 3456m/s to 3983 m/s as a function of ψ.Here ψ represents the angle between the lateral electric fieldand the crystallographic X-axis in the substrate major surface. A5MHz LFE device of (yxl)-58° LiNbO₃ withψ=0° was designed and tested in air. A major resonancepeak was observed with the motional resistance as low as 17Ω and the Q-factor value up to 10353. The test result iswell in agreement with the theoretical analysis, and suggests thatthe LFE LiNbO₃ device can be a good platform for highperformance resonator or sensor applications.