First Time of nanoscopic electrostatic drives pushing for ultrasonic transmission for gesture recognition

The design, fabrication, and acoustic characterization of an electrostatic ultrasound transducer based on lateral actuation is documented in this letter. Unlike cMUTs or pMUTs, this device-NED-MUT -does not use a membrane to generate pressure waves but instead displaces air using the volume of the chip. A single transmitter unit, composed of 258 actuators in an area of 3×3 mm
²
operating at 40 kHz, was capable of generating a pressure level of 87 dB (relative to 20 μPa rms) at a distance of 8.9 cm with an input voltage of 24V DC plus 24V AC. The measured performance makes the NED-MUT suitable for gesture recognition using ultrasound ranging.