Suppression of Transverse Spurious Modes in POI Substrate SAW Resonators

This paper proposes two new IDT structures to suppress higher-order lateral modes in POI-based substrate acoustic resonators. Finite element simulation results demonstrate that both structures alter the boundary conditions laterally, thereby suppressing transverse modes. Through parameter sweep simulations, we find that varying the number of slanted finger roots and the tilt angle of the busbar has a significant impact on lateral mode suppression in the resonator. As the number of slanted fingers and the tilt angle increase, the suppression effect improves. We identify the optimal busbar tilt angles for different numbers of slanted finger roots for the two structures. Moreover, the overall Q factor of Structure I is higher than that of Structure II, with a Q value of 1283.