A High Velocity and Wideband SAW on a Thin LiNbO3 Plate Bonded on a Si Substrate in the SHF Range

Although it was considered to be impractical to apply surface acoustic wave (SAW) filters in the super high frequency (SHF) range, a technology recently revealed that use of a thin piezoelectric crystal plate may recreate an impression of the past. This paper describes acoustic wave devices comprising the thin piezoelectric crystal plate, interdigital transducers placed on the plate, and an acoustic mirror bonded on a silicon substrate. First, it is theoretically and experimentally shown how the acoustic energy can be confined in the top surface even though longitudinal leaky SAW (LLSAW) is utilized. Then it is shown how the proposed structure is promising for the SHF range filters in mobile terminals upcoming next generation wireless access technology through comparing with the incredible high performance SAW (I.H.P. SAW) and a high velocity A1 Lamb wave resonator.