Research On Hot-wire MEMS Vector Hydrophone With Enhanced Sensitivity Structure

The Hot-wire MEMS Vector Hydrophone becomes one of hot topics in the study of sonar system because of its directional pattern in the form of dipole-shape and strong anti-interference ability.In this dissertation,a Hot-wire MEMS Vector Hydrophone is proposed and implemented,based on MEMS nano-wires structure,which could be widely used to various fields of hydroacoustic measurement.Through the theoretical and simulation analysis of sensitivity of the sensor and the two hot wire spacings,the heat dissipation power and the particle velocity,the geometrical dimensions and working conditions of the sensor are determined.This paper introduced a sensitivitized structure of double-cylinder,aimming at the problem of severe attenuation of sensitivity of the hot-wire MEMS particle velocity sensor worked in water.This structure sailed through fluid simulation analysis,optimized the design of sensitivitized structure.After that,a package structure for underwater circumstance was designed.The signal processing circuit including power modern,R/Vconversion modern and instrumentation amplifier module.Three kinds of R/V conversion circuit schemes--differential bridge circuit,Wheatstone bridge circuit and mirror current bridge circuit are analyzed and compared.The mirror current bridge circuit was chosen as the conversion circuit.The performance of Hot-wire MEMS Vector Hydrophone was tested.Through the air semi-anechoic chamber and the calibration device for underwater wave field of vector hydrophone test,we found that when the chanel was between 20~2000Hz,the acoustic signal was applified by sensitivitized structure about 10 dB.And the vector hydrophone's sensitivity reaches-199dB@800Hz in operating chanel between 20~800Hz.The sensor has a good figure-of-eight directivity independent,and the directivity curve smooth,lateral inhibition is about 30 dB.