一种压电式MEMS矢量水听器设计

Design of a Piezoelectric MEMS Vector Hydrophone

针对当前单只矢量水听器定向精度低,只能实现1/4象限内定向的问题,本文提出了一种压电式MEMS矢量水听器,期望利用压电效应和该结构提高水听器灵敏度,同时拓宽频带,实现360°范围内声源的准确定向.该水听器微结构包括由梁和4个相互垂直锚结构组成的力学传动单元和由压电薄膜构成的力电敏感转换单元两部分,通过梁结构直接接收声波信息,利用压电薄膜材料两端产生的电荷密度和电荷极性实现声音信号大小和声源方向的检测.建立了该水听器微结构的等效运动模型,在此基础上建立了微结构频率特性和传感数学模型,并进行了仿真验证.理论和仿真结果表明,该水听器频响范围拓宽至10kHz.

The current single vector hydrophone has the disadvantage of low orientation accuracy and can only realize orientation within a quarter of quadrant.Therefore,this paper proposes a piezoelectric MEMS vector hydrophone.It is desirable that the application of piezoelectric effect and ingenious structure may improve the sensitivity,broaden the frequency band,and realize the accurate orientation of the sound source within 360°.The vector hydrophone consists of two parts:apower transmission unit composing beam and four mutually perpendicular anchors,and sensing unit composing piezoelectric film.The beam structure directly receives the sound vibration signals,and the sensor can measure the magnitude and direction of vibration according to the charge quantity and electrode polarity on the surface of the piezoelectric film material in two dimensions.The equivalent motion model of the structure is establish,then the frequency characteristics and sensing mathematical model of the microstructure are established,and further simulation analysis is carried out.The theoretical and simulation results show that the frequency response range of the vector hydrophone is up to 10 kHz.