Low Power Capacitive Ultrasonic Transceiver Array for Airborne Object Detection

This work presents a low power ultrasonic transceiver line array enabling energy efficient airborne object detection. The line array is based on capacitive micromachined ultrasonic transducers (CMUTs), which utilize a dual-backplate MEMS technology, allowing a low bias and actuation voltage operation below 10V. Therefore, digital output ports of common microcontrollers (0-3.3V) are able to drive these devices sufficiently well and standard hardware of mobile devices can operate the array without the need of further voltage amplification. λ/2-pitch arrays consisting of three, five and seven transceivers are analyzed and compared in terms of ultrasonic frequency response, generated sound pressure levels and directivity both experimentally and theoretically. Finally, 2D object detection based on acoustic beam-steering through a phase delayed actuation is demonstrated with the seven transducers array to underline its practical potential.