A new layered structure ZnO/AlN/diamond, is studied for high-frequency and high electromechanical coupling (K 2 ) SAW devices. Theoretical study was performed to calculate the phase velocity and K 2 dispersion curves of the Rayleigh mode and its higher modes as well as the leaky waves. Both high values of K 2 (>4%) and acoustic velocities higher than 15 km/s are expected with this new structure according to the theoretical results. To confirm the simulation results, SAW filters were processed on ZnO/AlN/diamond structure. First experimental results are in agreement with the theory and confirm the high potential of this new structure high-performance and high-frequency SAW filters.