Central buoyant MEMS vector hydrophone of low-frequency and high sensitivity

The MEMS bionic vector hydrophone developed by North University of China has advantages of low frequency, miniaturization, high sensitivity, etc. But the sensitivity of the hydrophone is still low for detecting the week acoustic signals. How to enhance the sensitivity is a critical problem to the future developments. So a type of central buoyant microstructure is proposed, expecting to improve the sensitivity. And based on the acoustic research, the parameters of the central buoyant sphere is finally determined. The influences of the central buoyant microstructure on the sensitivity and the frequency band are analyzed by static analysis and fluid-structure interaction respectively. In order to verify the feasibility and performance, the hydrophone is tested in the standing wave field and in the real environment. Results show that the sensitivity of the hydrophone is -175 dB, the frequency ranges from 20 Hz to 500 Hz, which satisfies the requirement of detecting the ship radiation noise over a long distance, and the fluctuation range of frequency response curve is 1.5 dB. The directivity pattern of 8-shape is good(48.8 dB).