Solidly Mounted Longitudinally Excited A1 Mode Resonator Based on Linbo3/Metal/SIO2/SIC

For the first time, this work presents a solidly mounted (SM) longitudinally excited first-order antisymmetric lamb wave (A1) mode resonator with high-velocity support substrate (HS) and floating bottom electrode. Based on the X-cut LiNbO3/metal/SiO2/SiC substrate, HS-type A1 mode resonators have potential in achieving large bandwidth due to the large piezoelectric coefficient of LiNbO3. The maximum phase velocity of A1 mode can reach close to 7000 m/s, which is approximately twice that of conventional SAW. Additionally, this structure is easier for fabrication compared to the existing A1-mode resonator based on Bragg reflector (BR). The fabricated HS-type A1 mode resonators exhibit resonance frequencies (fs) near 5 GHz and electromechanical coupling coefficient $\left({k_t^2}\right)$ between 10% and 16%. Through further optimization, the new type A1 mode resonator will be a promising solution for 5G New Radio (NR) and Wi-Fi 7 band filters.