High-frequency and Low-loss SAW Devices Based on LiTaO3/Sapphire Hetero-structure

Abstract 5G communication imposes stricter requirements on filter performance, including operating frequency, insertion loss, and temperature stability. Surface acoustic wave (SAW) devices based on piezoelectric hetero-structures have emerged as a promising solution to meet these challenges. This work proposes SAW devices utilizing a LiTaO3/Sapphire hetero-structure, leveraging Sapphire’s high acoustic velocity and insulation properties to enhance frequency performance and reduce losses. LiTaO3/Sapphire hetero-structure were investigated theoretically and experimentally to optimize the designing parameters of LiTaO3 film. The implemented resonators exhibit high frequencies ranging from 2.84 to 3.63 GHz, achieving quality factors (Q) exceeding 2300 and a coupling coefficient over 8.5%. Additionally, a high-performance SAW filter operating at 3.43 GHz with a minimum insertion loss (ILₘᵢₙ) of 0.59 dB and excellent temperature stability was successfully achieved, further demonstrating the potential of LiTaO3/Sapphire hetero-structures for advanced 5G applications.