Suppression of Rayleigh wave spurious signal in ultra-wideband surface acoustic wave devices employing 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 single crystals

Abstract

The propagation characteristics of surface acoustic waves (SAWs) on rotated Y-cut X-propagating 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3(PMN-33%PT) substrate are theoretically analyzed. It is shown that besides the existence of a shear horizontal (SH) SAW with ultrahigh electromechanical coupling factor K2, a Rayleigh SAW also exists causing strong spurious response. The calculated results showed that the spurious Rayleigh SAW can be sufficiently suppressed by properly selecting electrode and its thickness with optimized rotating angle while maintaining large K2 of SH SAW. The fractional -3 dB bandwidth of 47% is achievable for the ladder type filter constructed by Au IDT/48oYX-PMN-33%PT resonators.

LiNbO3 Surface Acoustic Wave Resonators with Large Effective Electromechanical Coupling

“…Surface acoustic wave (SAW) devices have become the mainstream implementation of radio frequency (RF) filters in modern mobile transceivers because the SAW devices can fully meet the above requirements in terms of certain components of the wireless system. Different from the 4G communication, SAW filters, which are fabricated by cascading resonators, should have a higher and wider communication frequency band as the explosive increasing of mobile data traffic [10,11]. Because of this, SAW resonators with a high frequency, a large effective electromechanical coupling (k 2 ), a great temperature stability, and a high-quality factor are necessary [12,13].…”