Biomimetic resonant acoustic sensor accurately detects distant voices to reach the market


In 2018, professor Keon jae lee presented the first concept of a flexible piezoelectric acoustic sensor, inspired by the fact that humans can accurately detect distant voices using a multiresonant trapezoidal membrane with 20,000 hair cells. However, previous acoustic sensors could not be integrated into commercial products such as smartphones and AI speakers due to their large size.

In this work, the research team fabricated a mobile-sized acoustic sensor by adopting ultra-thin, high-sensitivity piezoelectric membranes. Simulation studies have proven that the ultrathin polymer under the inorganic piezoelectric thin film can expand the resonance bandwidth to cover the entire range of voice frequencies using seven channels. Based on this theory, the research team successfully demonstrated the miniaturized acoustic sensor mounted in commercial smartphones and AI speakers for biometric authentication and machine learning based voice processing.

The resonant mobile acoustic sensor has superior sensitivity and multi-channel signals compared to conventional condenser microphones with only one channel, and it showed very accurate and distant speaker identification with a small amount of voice training data. Speaker ID error rate has been significantly reduced by 56% (with 150 training data sets) and 75% (with 2,800 training data sets) compared to that of a device MEMS capacitor.

Professor Lee said, “Google has targeted the ‘Wolverine Project’ on remote multi-user voice separation for next-generation AI user interfaces. I think our multi-channel resonant acoustic sensor with abundant voice information is the best fit for this candidacy. ”

Professor Lee has also created a start-up Fronics Inc., in Korea and the United States to market this flexible acoustic sensor. This research was published in Scientists progress in February 2021.


KAIST ( is Korea’s first and best science and technology university. KAIST was established in 1971 by the Korean government to train scientists and engineers committed to the industrialization and economic growth of Korea.

Since then, KAIST and its 64,739 graduates have been the gateway to advanced science and technology, innovation and entrepreneurship. KAIST has become one of the most innovative universities with more than 10,000 students enrolled in five colleges and seven schools, including 1,039 international students from 90 countries.

On the precipice of its half-century anniversary in 2021, KAIST continues to strive to make the world a better place through the pursuit of education, research, entrepreneurship and globalization.

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Younghye Cho
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SOURCE KAIST (Korea Advanced Institute of Science and Technology)

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