High electromechanical coupling coefficient SAW resonator on Ta2O5/Al/LinbO3 structure for wide duplex gap application

This paper describes the development of high electromechanical coupling coefficient (K²) SAW resonator on a Ta₂O₅/Al/LiNbO₃ structure for wide duplex gap application. We have cleared that the optimum Ta₂O₅ thickness which the high performance SAW resonator without Rayleigh-mode spurious response could be realized. Also, the Ta₂O₅ film has an advantage of decreasing the film thickness compared with SiO₂ film. The developed SAW resonator shows the excellent performances which are low insertion loss, high attenuation, and high K² of 23%. So, we have exhibited the possibility of Ta₂O₅/Al/5°YX-LiNbO₃ structure for wide duplex gap application as the alternatives to the SiO₂/Al/5°YX-LiNbO₃ structure. And, the SAW resonator has the possibility to apply to Band IV duplexer.