Performance optimization of plate-mode sensors with bi-layered structure

The acoustic characteristics of plate-mode sensors with bi-layered structures composed of a piezoelectric film and a non-piezoelectric substrate are studied by numerical calculations using the transfer matrix method. Performances of the sensors can be evaluated based on the theoretical calculations of the dispersion curves, electromechanical coupling coefficients and sensitivities of the plate-mode sensors with a bi-layered structure. In order to obtain the optimized operating conditions of the sensors, the operating mode, frequency and the ratios of thickness of piezoelectric film to that of the substrate are evaluated when the sensors are applied in gas and/or liquid conditions.