"Lollipop-shaped" high-sensitivity Microelectromechanical Systems vector hydrophone based on Parylene encapsulation
"Lollipop-shaped" high-sensitivity Microelectromechanical Systems vector hydrophone based on Parylene encapsulation
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DOI：
10.1063/1.4927333
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发表时间：
2015-07-28
影响因子：
3.2
通讯作者：
Liu, Jun
中科院分区：
文献类型：
--
作者：
Liu, Yuan;Wang, Renxin;Liu, Jun
本文提出了通过增加纤毛敏感面积和改善Parylene薄膜绝缘性来提高MEMS矢量水听器灵敏度的方法。首先，将低密度球体与纤毛结合成“棒棒糖形状”，这可以大大增加传感面积。建立了“棒棒糖形”MEMS矢量水听器灵敏度的数学模型，并通过仿真分析了不同结构参数对灵敏度的影响。其次，MEMS矢量水听器通过绝缘聚对二甲苯膜的共形沉积进行封装，这使得水下声学监测无需任何类型的透声封装。测试结果表明，该结构的灵敏度达到了-183dB（500 Hz 0 dB at 1V/mu Pa），比传统的纤毛型MEMS矢量水听器提高了10 dB以上。频率响应灵敏度每倍频程增加6dB。该水听器的工作频带为20-500 Hz，“8”字形指向性凹点深度超过30 dB，具有良好的水声应用前景。(C)2015 AIP Publishing LLC.
This paper presents methods of promoting the sensitivity of Microelectromechanical Systems (MEMS) vector hydrophone by increasing the sensing area of cilium and perfect insulative Parylene membrane. First, a low-density sphere is integrated with the cilium to compose a "lollipop shape," which can considerably increase the sensing area. A mathematic model on the sensitivity of the "lollipop-shaped" MEMS vector hydrophone is presented, and the influences of different structural parameters on the sensitivity are analyzed via simulation. Second, the MEMS vector hydrophone is encapsulated through the conformal deposition of insulative Parylene membrane, which enables underwater acoustic monitoring without any typed sound-transparent encapsulation. Finally, the characterization results demonstrate that the sensitivity reaches up to -183 dB (500 Hz 0dB at 1V/mu Pa), which is increased by more than 10 dB, comparing with the previous cilium-shaped MEMS vector hydrophone. Besides, the frequency response takes on a sensitivity increment of 6 dB per octave. The working frequency band is 20-500 Hz and the concave point depth of 8-shaped directivity is beyond 30 dB, indicating that the hydrophone is promising in underwater acoustic application. (C) 2015 AIP Publishing LLC.