Compact High-Performance Vibration Sensor Based on Single-Backplate MEMS Technology

The quality of voice communication using True Wireless Stereo (TWS) is not ideal in noisy environments. Existing two microphone beamforming solution is unable to isolate the users voice reliably in all possible acoustic environment. Here, the use of bone-conducted voice pickup holds promise for improving voice calling quality. There are some microphone-based bone-conducted voice pickup solutions on the market that either have insufficient vibro-acoustic performance or are not ideal for use in consumer electronics due to their size. This work conceptualizes a novel vibration sensor that overcomes the limitations of existing solutions to address the gap in technology. The proposed concept is based on industry-proven single-backplate Micro-Electro-Mechanical Systems (MEMS) technology with an attached proof-mass that allows bone-conducted voice pickup. Simulation and characterization of the fabricated MEMS and assembled prototypes show that the proposed solution can achieve a high vibration sensitivity of −29.7 dBV/g and a high Signal to Noise Ratio (SNR) of 70 dBA, in a small $3.0\times 2.0\times 0.8$ mm3 package size. Therefore, it is overall well suited for voice communication using bone-conducted voice in TWS.