Emission profile of multi-membrane CMUT for in-air object localization

This work presents novel Capacitive Micromachined Ultrasonic Transducers (CMUTs) and their characterization in terms of ultrasound directionality. The devices are formed by 27 membranes, integrated on the same die and connected in parallel, featuring a 1 μm gap between the membrane and the bottom electrode, and directly coupling to air at 2.23 MHz. Exploiting the information on the amplitude and delay of the received ultrasonic waves, a directionality profile showing a 14° full width at half maximum (FWHM) and a 0.5-5 cm distance operative range are demonstrated. Object localization experiments show a 2D relative position reconstruction error around 5%.