A SAW resonator with improved temperature characteristics includes a single crystal piezoelectric substrate of symmetry 3 m, providing propagation of leaky waves with quasi-shear horizontal polarization and squared electromechanical coupling coefficient exceeding 5%. A SiOx overlay having a flattened surface covers the electrode pattern. Electrode thicknesses range from about 0.1% to about 10% of an acoustic wavelength and the SiOx thickness ranges between zero and 30% of an acoustic wavelength of a surface acoustic wave excited on the surface of the substrate. The piezoelectric substrate has an orientation defined by Euler angles (0±3°, μ, 0±3°), with angle μ=90°−μ′ and rotation angle μ′, which depends on material of a piezoelectric substrate and thicknesses of electrodes and SiOx overlay. Such orientations simultaneously combined with optimized thicknesses of electrodes and SiOx overlay provide for improved performance in RF applications with improved temperature characteristics.