Acoustoelectric Voltage Sensor Based on S0 Mode Lamb Wave Resonator with Millivolt Resolution

Surface acoustic wave (SAW) voltage sensors merely based on piezoelectric deformation used to being applied with a scale of volts to kilovolts resolution. Combined with acoustoelectric (AE) effect, the SAW voltage sensor meets a new opportunity for development because both acoustic phase velocity and piezoelectric deformation are sufficiently utilized to modulate oscillation frequency. The intensity of acoustoelectric effect depends on the piezoelectric coupling and carrier mobility so the combination of lamb wave mode with electromechanical coupling coefficient (K ² ) one order of magnitude higher than traditional SAW mode and 2D material with high carrier mobility would support a meaningful breakthrough. The resolution of acoustoelectric voltage sensor would be improved to a millivolt range.This paper will derive an acoustoelectric coupling model behind the AE voltage sensor, based on which a novel embodiment of graphene-LiNbO 3 film composite structure lamb wave voltage sensor is designed. Aiming at large K ² and high carrier drift velocity, the device structure and parameters are optimized. The simulation results show that the relative acoustic velocity shift achieves 1‰ when the input voltage equals 8mV. This effect could not only sense millivolt voltage but also lead to a low power consumption and voltage-controlled velocity shifter. Millivolt voltage signal transmission via an acoustic resonator will be feasible too.