Development Of Three-axis Bionic Piezoresistive Vector Hydrophone Based On MEMS Technology

Vector hydrophone can not only get the scalar pressure of the sound filed, but also get thevector velocity information.Two-dimensional MEMS vector hydrophone manufactured byNUC has the advantages of small size and good low frequency response and rigid fixing.However, the vector hydrophone can only realize the planar orientation, which is unable tofinish the target orientation under water. For realization of underwater acoustic target spatialorientation, a three-axis bionic piezoresistive vector hydrophone based on MEMS technologyis researched in this paper.Firstly, a three-axis microstructure of MEMS has been designed according to the fishlateral line structure characteristics. Then application the knowledge of acoustic, materialmechanics, elastic mechanics, combined with the finite element analysis software ANSYS,the relationship between structure parameters and stress with frequency is obtained about thethree-axis microstructure of MEMS. On the basis of considering the three-axismicrostructure’s sensitivity and natural frequency, the parameters of the three-axismicrostructure of MEMS are confirmed. According to simulation, the location of theresistance is determined through the simulation. and the connection of the Wheatstone Bridgeis designed in this paper.According to the fabrication technology, an entire series of independent processes forthree-axis MEMS microstructure fabrication and the layout is designed. According to the sizeand application way of the MEMS microstructure, MEMS chip packaging is finished. Aftervertical cilia with MEMS microstructure integrated, acoustic package and signal extractioncircuit designed, The prototype of MEMS three-axis bionic piezoresistive vector hydrophoneis made out.Finally, the tests of MEMS three-axis bionic piezoresistive vector hydrophone arefinished. The paper firstly verifies the structural characteristics of the microstructure by vibration table, Base on the above test, the performance of MEMS three-axis bionicpiezoresistive vector hydrophone is verified by the calibration device. The frequency responsetest shows that the sensitivity of the hydrophone is no less than-200dB(0dB=1V/μPa, andthe voltage amplification factor is300) below800Hz, and the frequency response curve isapproximately linear growth. Directivity tests display that the hydrophone has a good"8"-shaped directivity, and the directivity resolution is not less then30dB, and asymmetry ofthe maximum axial sensitivity value is less than1.2dB. Hydrostatically test show thehydrophone can withstand2MPa hydrostatic pressure which the working depth is200m.