Data-Over-Sound With PMUTs

Abstract

Data-over-sound is an emerging technology for digital communication which uses frequencies at the upper bounds of human hearing, usually between 15 kHz to 25 kHz. We report a successful development of Piezoelectric Micromachined Ultrasound Transducers (PMUTs) for low-power data-over-sound applications. Piezoelectric thin films used in PMUTs can have high residual tensile stresses ranging from 300 MPa to 1.5 GPa. These stresses have the effect of increasing the resonant frequencies of the transducers, making it a challenge to fabricate low frequency devices. Using the optimum dimensions by estimating the net residual stress in the fabricated diaphragms, transducers suitable for a frequency range of 17 kHz to 21 kHz were fabricated, capable of generating as much as 83 dB of sound pressure level at a distance of 5 cm in continuous operation.

Mixed Nonlinear Response and Transition of Nonlinearity in a Piezoelectric Membrane

“…4 MEMS-based ultrasonic transducers are of immense interest for their application in proximity sensing, 5 gesture recognition, 6 medical imaging, 7 photoacoustics, 8 and data-oversound communication. 9 These transducers are preferred over conventional bulk ultrasonic transducers due to low power consumption, 10 low cost, and good acoustic impedance matching. 10 These transducers are generally of two types: capacitive micromachined ultrasonic transducer (CMUT) 11,12 and piezoelectric micromachined ultrasonic transducer (PMUT).…”

“…Microelectromechanical system (MEMS)-based devices have been extensively studied and used in applications such as inertial navigation, digital light manipulation, radio frequency (RF) communication, biosensors, and several types of transducers . MEMS-based ultrasonic transducers are of immense interest for their application in proximity sensing, gesture recognition, medical imaging, photoacoustics, and data-oversound communication . These transducers are preferred over conventional bulk ultrasonic transducers due to low power consumption, low cost, and good acoustic impedance matching .…”