FEM/BEM simulation and experimental study of LLSAW resonator characteristics on YZ-LiNbO/sub 3/

The high velocity (above 6000 m/s in LiNbO/sub 3/) of the longitudinal leaky SAW (LLSAW) mode makes it attractive for use in high frequency SAW devices in the 2-3 GHz range. We have investigated, both experimentally and theoretically, the dependence of one-port LLSAW resonator performance on YZ-LiNbO/sub 3/ on the metallization thickness and metallization ratio. The results indicate a strong dependence of the Q factor and resonance frequency on the aluminum thickness. The observed behaviour is addressed with the help of simulations using a combined FEM-Green's function method. Based on the simulated and experimental data, the optimal aluminum thickness is found to be approximately 8%.