Piezoelectric micromachined ultrasonic transducers in consumer electronics: The next little thing?

This paper describes air-coupled piezoelectric micromachined ultrasonic transducers (PMUTs) for consumer electronics applications including time-of-flight range-finding, proximity and presence sensing, and gesture recognition. These applications require sensors that are small size, low-cost, and ultra-low-power, all of which are characteristics of PMUTs.