Abstract
In this letter, we investigate the methods for suppressing transverse spurious modes in wideband shear-horizontal surface acoustic wave (SH-SAW) resonators by combining piston-mode operation with meshed busbar design to modify the velocity profile along the transverse direction and improve lateral energy confinement. The reported SH-SAW resonators, implemented on a thin-film lithium niobate on insulator (LNOI) platform, achieve a large effective electromechanical coupling coefficient ( k_(\text eff)²) of 35.3%, a high quality factor (Bode- Q_(\max)) exceeding 800, and a high admittance ratio (AR) of 75.3 dB at 791 MHz, yielding a high figure of merit (FoM = k_(\text eff)²⋅ Q_(\max)) of 283 while featuring a near spurious-free response. The proposed device is also compared with other reference designs implemented using conventional spurious mode suppression techniques on the same chip and demonstrates superior performance.