A High-Sensitivity Air-Coupled PMUT with Force Feedback Control for Full-Loop Ringdown Suppression and Bandwidth Enhancement

A high-sensitivity air-coupled PMUT (piezoelectric micromachined ultrasonic transducer) integrated with an advanced electrical control module is presented, surpassing state-of-the-art performance in multiple aspects. 1) An optimized electrical module with precise phase shift and attenuation control is introduced, effectively eliminating the ringdown effect with clean ripples in transmission. 2) A force feedback control loop (FFCL) is integrated, enabling tunable bandwidth performance while also suppressing ringdown effects during reception. By combining the excitation control module and the FFCL, the PMUT system significantly mitigates the ringdown effect across the full transceiving loop. More importantly, the control module resolves the inherent trade-off between bandwidth and sensitivity, achieving a remarkable reduction in the full-loop ringdown effect with minimal sensitivity loss. This work establishes a foundation for advanced air-coupled ultrasonic sensing systems with enhanced performance and versatility.