Ultra-Wideband Surface Acoustic Wave Devices Using Cu-Grating/Rotated-YX-LiNbO3-Substrate Structure

Abstract

This paper discusses the application of Love mode propagating on Cu-grating/rotated YX-LiNbO₃-substrate structure to the development of ultra-wideband and low-loss RF surface acoustic wave (SAW) filters. Theoretical analysis suggested that high performance resonators with very small capacitance ratio would be realised using Cu gratings with a thickness of several percent of wavelength. It was also suggested that in particular, on 15°YX-LiNbO₃-substrate structure, the spurious response due to Rayleigh mode could effectively be suppressed. An IDT-type one-port SAW resonator and a ladder-type SAW filter were fabricated on the Cu-grating/15°YX-LiNbO₃-substrate structure, and their high performances are demonstrated with discussion.