With the development of fifth-generation wireless systems, the Internet of Things, and health services, surface acoustic wave (SAW)-based filters and sensors have attracted considerable interest. This study presents a new structure for high-frequency, large-coupling, and low-cost SAW devices that helps implement high-frequency and wideband filters and enhances the sensitivity of sensors. The structure is based on 15°Y-X LiNbO₃, thin SiO_x/SiN_x bilayer overlay, and Al electrodes. Furthermore, a low-cost fabrication process for SAW devices based on this structure was designed. Simulation and experimental results show that the bilayer substantially weakens the leaky nature of shear-horizontal-type SAWs with a phase velocity higher than that of a slow-shear bulk wave in LiNbO₃. Thus, the limitation related to the velocity of 4029 m/s was overcome, and the phase velocity reached approximately 4500 m/s, which means an increase of 50% compared with that of conventional Cu/15°Y-X LiNbO₃ devices. Consequently, the frequency dramatically increases, and the quality of the SAW response is ensured. Simultaneously, a large electromechanical coupling factor close to 20% can be achieved, which is still suitable for wideband filters and sensors with high energy transduction coefficients. This new structure is expected to become a major candidate for SAW devices in the future.

随着第五代无线系统，物联网和健康服务的发展，基于表面声波（SAW）的滤波器和传感器引起了人们的极大兴趣。这项研究提出了一种用于高频，大耦合和低成本SAW器件的新结构，该结构有助于实现高频和宽带滤波器并增强传感器的灵敏度。结构基于15°YX LiNbO ₃，薄SiO _x / SiN _x双层覆盖层和铝电极。此外，基于该结构，设计了用于SAW器件的低成本制造工艺。仿真和实验结果表明，在LiNbO ₃中，双层明显削弱了水平剪切型声表面波的泄漏特性，其相速度高于慢剪切体波的相速度。因此，克服了与4029 m / s的速度有关的限制，相速度达到了约4500 m / s，这意味着与传统的Cu / 15°YX LiNbO ₃相比增加了50％。设备。结果，频率急剧增加，并且确保了SAW响应的质量。同时，可以实现接近20％的大机电耦合系数，这仍然适用于具有高能量转换系数的宽带滤波器和传感器。这种新结构有望在将来成为SAW器件的主要候选产品。