Abstract
This study presents a novel piezoelectric MEMS microspeaker with two pairs of single-curved actuators to implement multiple piston-modes for bandwidth enhancement. The proposed design has four features: (1) two-unit-array: providing double sound pressure output, (2) outer/inner actuators: constructing both low-frequency and high-frequency piston-modes to expand bandwidth, (3) dual-electrode: improving the actuation of spring-diaphragm structure, (4) crossover-driving method: enhancing SPL in specific frequency range. Measurements demonstrate the proposed design has achieved an almost two-fold wider bandwidth (60Hz~11kHz) in 65dB SPL under 0.7V rms (15V DC ) input voltage in standard ear simulator.