Design of high-frequency surface acoustic wave resonator based on IDT/etched-AlN/IDT/AlN/diamond multilayer structure

Abstract This study presents a high-frequency surface acoustic wave (SAW) resonator based on interdigital transducers (IDT)/etched aluminum nitride (AlN)/IDT/AlN/diamond multilayer structure. Through COMSOL simulations, the influence laws of the piezoelectric layer thickness, the position of the second electrode, and the electrode thickness on the device’s phase velocity ( V p ), electromechanical coupling coefficient ( K 2 ), and quality factor ( Q ) are systematically analyzed. The results show that the multi-layer structure significantly enhances energy localization efficiency through a dual-IDT coupling mechanism, achieving a V p of 11 210 m s −1 compared to a traditional etched AlN structure. The K 2 is elevated to 3.09%, and the Q value reaches 2480. The optimized resonator achieves a quality factor figure of merit of 76.6 at a frequency of 5.57 GHz, with comprehensive performance surpassing that of existing AlN/diamond-based SAW devices. This research presents a high-frequency SAW device design scheme applicable to fields such as 5G communications and high-frequency signal processing.