Ultrahigh Q Lithium Niobate Resonator With Annular Interdigital Electrode Structure

This article focuses on a lithium niobate (LN) surface acoustic wave (SAW) resonator with an annular interdigital transducer (AIDT) structure. The fundamental working principles and structural characteristics of this resonator are analyzed. Due to the closed and regular form of the electrode configuration, parasitic SAW reflections are eliminated, which is expected to significantly enhance the device’s Q factor. Finite element method (FEM) simulations were conducted to optimize the device’s performance. A high-performance LN SAW resonator was successfully microfabricated using micro-nano processing technology. The fabricated device demonstrated a resonant frequency of 22.22 MHz and an impressive Q factor of 12245, which is 2–3 times higher than that of conventional SAW resonators with interdigital electrodes, while its surface area is only one-third of their size. These results offer significant insights and a valuable reference for the development and application of SAW resonators with annular interdigital electrode structures in future research.