Broadband Acoustical MEMS Transceivers for Simultaneous Range Finding and Microphone Applications

This work presents capacitive ultrasonic transceivers based on a dual-backplate MEMS microphone technology. The transducers exploit mechanical and acoustical system resonances in the low ultrasonic frequency range up to 100 kHz for both sending and receiving of ultrasonic signals. Requiring below 10V bias voltage and using standard MEMS microphone housings with dimensions of 4x3x1 mm
³
, the proposed system allows an integration into space and power critical systems like e.g. smartphones. While the ultrasonic transceiver functionality enables proximity sensing and presence detection applications, state-of-the-art audio performance of 68 dB(A) signal-to-noise ratio (SNR) is maintained.