高灵敏宽频带声压/声压梯度复合式MEMS水听器研究

There is an urgent need to develop a hybrid vector hydrophone with high performance and small volume for the air-dropped sonobuoy and the underwater small weapon platform. In order to solve the problem that the cilium MEMS bionic vector hydrophone can’t measure the information of acoustic pressure and there exists the problem of port and starboard ambiguity in the Direction of Arrival estimation, A hybrid sensitive way that is composed of the information of the acoustic pressure/pressure-gradient is proposed to form unilateral directivity. In order to solve the problem that sensitivity and working frequency bandwidth of the current cilium MEMS vector hydrophone are constrained, a four-element array sensitive microstructure is proposed, which realizes the acoustic pressure-gradient measurement with high sensitivity and wide bandwidth. The acoustic pressure/pressure-gradient hybrid MEMS hydrophone with high sensitivity and wide frequency bandwidth is put forward to solve two key scientific problems, one is the sensitive mechanism of acoustic direction based on acoustic pressure/pressure-gradient information, and the other is the coupling relationship between the sensitivity and the frequency response range of the four-element array microstructure. The purpose of this project is to develop a non-planar microstructure manufacturing technology and complete the system integration. Finally the sensitivity of the MEMS vector hydrophone is expected to be improved by 10～15dB, with the frequency response range expanded 2~4 times, which could meet the need of multi-parameters measurement in acoustic field. Therefore, the proposed acoustic pressure/pressure-gradient hybrid MEMS hydrophone has the characteristic of distinguishing the port and starboard, high sensitivity and wide frequency bandwidth. This project would lay a theoretical and technological foundation for the engineering application of MEMS hydrophone.

空投声呐浮标和水下小尺寸武器平台对高性能、小体积复合式矢量水听器提出了迫切需求。针对目前纤毛式MEMS仿生矢量水听器不能测量声压信息，目标方位估计存在左右舷模糊的问题，本项目提出声场声压及声压梯度信息复合敏感方式，形成单边指向性；针对目前水听器的声压梯度灵敏度和工作频带相互制约的问题，本项目提出四元阵列敏感微结构，实现对矢量信息高灵敏宽频带的测量。将两者有机结合，优势互补，提出一种高灵敏宽频带声压/声压梯度复合式MEMS水听器，解决基于声压/声压梯度信息的声源方位敏感机制以及四元阵微结构灵敏度与频响范围之间的耦合关系这两个关键科学问题；开发一套非平面微结构一体化加工工艺，完成系统集成，最终实现MEMS矢量水听器灵敏度提高10～15dB，频响范围拓展2～4倍，满足声场多参量测量的需求，具有分辨左右舷、高灵敏宽频带的特点，为MEMS水听器的工程应用奠定理论和技术基础。

矢量水声传感器作为一种能够同时测量声场中标量和矢量信息的新型水下声传感器，受到国内外水声领域的高度关注。中北大学结合压阻效应、MEMS技术、仿生机理及水声原理研制的纤毛式MEMS仿生矢量水声传感器，是一款小体积、矢量性好的水声传感器。然而，当前纤毛式MEMS仿生矢量水声传感器灵敏度和工作频带相互制约，且只能测量声场中的矢量信息（声压梯度），方位估计时存在左右舷模糊的问题。为了进一步改善其性能和推进其工程化应用，我们以单边指向性的形成方法为理论基础，提出了声压-声压梯度复合式MEMS水声传感器的总体设计方案，通过电容式MEMS声压水声传感器来实现声压物理参量的测量，通过纤毛式MEMS仿生矢量水声传感器来实现声压梯度参量的测量，并针对当前纤毛式MEMS仿生矢量水声传感器灵敏度和工作频带相互制约的问题，提出了阵列式MEMS矢量水声传感器。并介绍了纤毛式MEMS仿生矢量水声传感器和电容式MEMS声压水声传感器的工作原理。.声压/声压梯度复合式MEMS水声传感器的矢量通道采用阵列式设计，纤毛长度分别为2mm、3mm、5mm、8mm，标量通道采用电容式声压通道方案，振动薄膜半径2mm，空腔高度4um。工作频带为5Hz~5000 Hz，声压通道灵敏度为-170dB，声压梯度通道灵敏度为-170 dB @1kHz，具有良好的“8”字余弦指向性，阵列式MEMS矢量水声传感器实现了高灵敏宽频带的测量。抗静水压达到20MPa，抑制流激噪声20dB，大幅提高复合式MEMS水听器的可靠性和实用性，最终形成完整的复合式MEMS水听器的水下传感理论、设计、制造和测试技术体系，为促进我国自主知识产权的低成本、高性能MEMS传感器件奠定坚实的理论和技术基础。.复合式MEMS水声传感器能在驻波桶中准确的获得声目标信号的方位信息，解决了纤毛式MEMS仿生矢量水声传感器目标方位估计时存在的左右舷模糊问题。并且复合式MEMS水声传感器具有良好的抗温度、抗冲击和承压能力。本文的研究为声压-声压梯度复合式MEMS水声传感器的工程化应用奠定了良好的基础。