▢ Piezoelectric MEMS Resonant Microphone Arrays (RMA) for Lung Sound Monitoring
Development of novel piezoelectric MEMS resonant microphone arrays (RMAs) for lung sound detection and classification, achieving ultra-high sensitivity with a signal-to-noise ratio (SNR) of 79–98 dBA. The technology enables improved detection of wheezing sounds compared with conventional microphones and provides a pathway toward wearable electronic stethoscopes for continuous lung sound monitoring.
Relevant Publications
- Sengupta, Anik, Akash Roy, Hongxiang Gao, Matin Barekatain, Hai Liu, and Eun Sok Kim. “Wearable Stethoscope Based on Resonant Microphone Array with Wireless Data Transfer.” In 2024 IEEE 37th International Conference on Micro Electro Mechanical Systems (MEMS), pp. 101-104.
- Liu, Hai, M. Barekatain, A. Roy, S. Liu, Y. Cao, Y. Tang, A. Shkel and E.S. Kim, “MEMS Piezoelectric Resonant Microphone Array for Lung Sound Classification,” Journal of Micromechanics and Microengineering, 33, No. 4 (2023), 044003..
- Liu, Hai, Song Liu, Anton A. Shkel, Yongkui Tang, and Eun Sok Kim. “Multi-band MEMS resonant microphone array for continuous lung-Sound monitoring and classification.” In 2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS), pp. 857-860. IEEE, 2020. Outstanding Student Paper Award Finalist (18/275).
- Liu, Hai, Song Liu, Anton A. Shkel, Yongkui Tang, and Eun Sok Kim. “MEMS resonant microphone array for lung sound classification.” In 2019 IEEE International Electron Devices Meeting (IEDM), pp. 34-4. IEEE, 2019.
▢ Active Noise Cancellation with MEMS RMA
Active noise cancellation (ANC) systems using MEMS resonant microphone arrays (RMAs) for hearing aids. Two RMAs were designed to separately capture speech and environmental noise, enabling improved noise cancellation compared with conventional microphones. The high signal-to-noise ratio (SNR) of RMAs achieved noise reduction of −20 to −25 dB, particularly in low-noise environments.
Relevant Publications
- Liu, Hai, Song Liu, Anton A. Shkel, and Eun Sok Kim. “Active noise cancellation with MEMS resonant microphone array.” Journal of Microelectromechanical Systems 29, no. 5 (2020): 839-845.
▢ Ultrasonic Propulsion
Acoustic Propulsion in air by synthesis jets produced by ultrasounds.
Relevant Publications
- Liu, Hai, A. Roy, Y. Tang, M. Barekatain and E.S. Kim, “Ultrasonic Air-Borne Propulsion Through Synthetic Jets,” Solid-State Sensor and Actuator Workshop, Hilton Head Island, SC, June 5 - 9, 2022, pp. 226 - 229.