A Single Chip Directional Loudspeaker Based on PMUTS

This paper reports a highly directional air-coupled parametric loudspeaker using a single chip of piezoelectric micromachined ultrasonic transducers (pMUTs). Compared with the state-of-art technologies, three distinctive advancements have been achieved: (1) a micromachined parametric array based on CMOS-compatible bimorph AlN pMUTs; (2) generation of highly directional audible sound with a half power beam width less than 5 degrees; and (3) generation of multiple audible frequency using a single chip with 246 pMUT elements in a footprint of 13mm by 13mm. As such, the proposed AlN pMUT parametric array could open up a new class for low-power portable directional loudspeakers for private communication and so on.