Analysis of the Wave Modes for Super-High Frequency SAW Devices on the SiO2/IDT/LiNbO3 Structure

We study the influence of wave propagation direction on the SAW modes excitation and their characteristics in the SiO
2
/IDT/128°Y-cut LiNbO
3
structures. The three-dimensional finite element method analysis reveals that the multilayer structure can support the Love wave, Rayleigh wave, Sezawa wave, 1
^st
Love wave, and 2
^nd
Rayleigh wave. Consistent with the measured result of the super-high frequency (2–10 GHz) SAW devices, the Love wave mode is coupled with the Rayleigh wave mode. Meanwhile, because of the effect of the electrode, symmetric and antisymmetric modes of the Rayleigh wave and Sezawa wave appear simultaneously. This work guides further optimization of the device at super-high frequency.