Transverse Modes in I.H.P. SAW Resonator and Their Suppression Method

We discuss transverse modes in a resonator on a multilayer substrate with a thin piezoelectric plate. A generation mechanism of the transverse mode response in I.H.P. SAW (Incredible High-Performance SAW)resonator with a LiTa03 plate is analyzed by using FEM simulations, and it is shown that a slowness curve of the I.H.P. SAW structure is changed significantly compared with a standard 42° Y-X LiTa03 substrate. A new tilted resonator structure is proposed to suppress the transverse mode spurious. It is found that the tilted resonator with a small tilted angle can suppress the spurious response successfully with maintaining a high-Q factor.