Design And Optimization Of MEMS Electronic Stethoscope

Cardiovascular disease has seriously damaged human life and health,and its pathogenesis is closely related to the function of the heart.Early screening and accurate diagnosis of cardiovascular diseases are particularly important,and its medical value can not be ignored.As an important physiological signal in the human body,heart sound can not only reflect the health status of the heart,but also provide diagnostic information about cardiovascular diseases,so it has important research value.The heart murmur signal which reflects the pathological information belongs to the weak signal of the human body,and the acquisition of high-quality heart sound signal is the premise to improve the diagnostic accuracy.Inspired by the auditory mechanism of human ear,a MEMS heart sound sensor based on concave hollow bionic cilia is proposed in this paper.Firstly,the ciliated MEMS heart sound sensor is theoretically studied and simulated,and the structure of the ciliated MEMS heart sound sensor is optimized based on the theoretical analysis.Secondly,the electrical insulation and sound transmission packaging methods of the sensor are studied,and the integrated design of acoustic impedance matching package is realized by using the thin film support structure,which reduces the sound propagation attenuation loss of heart sound signal transmitted in different media and improves the signal-to-noise ratio of ciliated MEMS heart sound sensor.And through the sensor performance test and data calibration to analyze the characteristics of the collected heart sound signal,verify the feasibility of the ciliated MEMS heart sound sensor to detect the full-band heart sound signal.Finally,the registration test of medical electrical equipment is carried out on the whole system of ciliated MEMS electronic stethoscope.The results show that the sensitivity of the designed heart sound sensor is-206.9 d B@200Hz,the working bandwidth is 200.800 Hz,and the signal-to-noise ratio is 26.471 d B.The waveform of the heart sound signal is clear and accurate,which meets the requirements of medical electrical equipment.This study provides technical support for improving the detection sensitivity of heart sound signal and realizing more effective heart sound auscultation,and has a good application prospect in early monitoring and prevention of coronary heart disease.