N77 band demands wide bandwidth and low insertion loss in surface acoustic wave （SAW） filters. However, conventional resonators that employ low-velocity acoustic modes and single functional layer substrate structures face challenges in simultaneously achieving high frequency and wide bandwidth. To address the challenges, solidly mounted SAW resonators based on X-37°Y lithium niobate （LiNbO₃, LN） films combined with SiO₂/Ta₂O₅ Bragg reflector layers were designed and fabricated. First, the operating mode of the resonators was chosen to be the high-phase-velocity S₀ Lamb wave. Then, the optimal thicknesses of the thin film materials used in the resonator were determined by simulating the influence of each layer’s thickness on device performance. Subsequently, based on these structural parameters, a set of resonators for N77 band with electrode periods, ranging from 1.40 μm to 1.86 μm, was fabricated and tested. The results indicate that the measured data closely match the simulation outcomes. The fabricated resonators show a large electromechanical coupling coefficient （k² exceeding 22%） and high-quality factor （Q_max exceeding 900）. Furthermore, the figure of merit （FoM） exceeds 200, showcasing superior performance when compared to other resonators utilizing the same acoustic mode and indicating potential applications in filters for N77 and other 5G bands.