Love Mode SAW Device Based on ZnO-SiO₂ Guiding Layer

A Love wave sensor with a dual waveguide layer structure was designed and simulated. Using ST-90°X quartz as the piezoelectric substrate, the study investigated the deposition of x ZnO -y SiO 2 guiding layers of different thicknesses on the substrate. The analysis of phase velocity and admittance correlations indicates that the optimal thickness ranges for the SiO 2 and ZnO guiding layers are 0.05∼0.1 λ and 0.005∼0.015 λ , respectively. When a 0.3 μmZnO-1 μmSiO 2 dual waveguide layer is deposited on top of the surface acoustic wave (SAW) devices, operating frequency close to 237.898 MHz, and the device quality factor ( Q ) is 3999.4. In addition, based on a single-period frequency domain analysis, 3D full models of the sensors (delay line structure) are constructed. Time-domain calculations are used to detail the displacement variation of the Love wave sensor based on a 0.3 μmZnO-1.0 μmSiO 2 /ST-90°X quartz structure and the shear horizontal (SH) wave sensor based on ST-90°X quartz. Finally, the changes receiver voltage and insertion loss demonstrate that the ZnO-SiO 2 waveguide layer has a positive effect on reducing the device loss.