Research Of Two-dimensional Vector Hydrophone's Miniaturization Construction Design And Manufacture

A vector hydrophone is combined with traditional omni-directional pressure sensor and dipole directional particle velocity sensor independent of frequency, which can simultaneously and collocately measure orthogonal components of particle velocity as well as pressure at single point in space. So the technology associated with vector hydrophone becomes a very important investigative aspect in underwater acoustic field. But there are still some limitations in following topics about vector hydrophones: high sensitivity; ultra-low-frequency detection; miniaturization of vector hydrophone; self-noise control and so on. This thesis tries to solve the problem of miniaturizing vector hydrophone by using compact and high sensitivity accelerometer.This thesis consists of three parts. First is theoretical derivation of vector hydrophone's working principle; Second is description of electro-acoustic parameters of vector hydrophone; and the last is detailed introduction of two kinds of accelerometers and three vector hydrophones made by author.Two kinds of accelerometers are used—conventional piezoelectric accelerometer and MEMS capacitive accelerometer ADXL203.And the author made three vector hydrophones(number 1, number 2, number 3). Measurement results show that the vector channel of number 1 hydrophone has an excellent directivity characteristic, its resolution k_a is higher than 20dB, and its sensitivity is -179dB(1000Hz,0dB re 1v/μPa); directivity of number 2 and number 3 hydrophones has some defects because of inherent white noise and low signal-to-noise ratio, sensitivity of number 2 hydrophone is -187.8dB(500Hz), sensitivity of number 3 hydrophone is -181.8dB(500Hz). Pressure sensitivity of all three hydrophones is about -202dB.At last, measurement results also show that the directivity and sensitivity characteristics of number 1 hydrophone meet expected results, and it can be regarded as the reference of designing and making miniature and high sensitivity vector hydrophones; number 2 and number 3 hydrophones are suited for low-frequency and narrow band vector hydrophone because of inherent white noise from accelerometer.