MEMS仿生矢量水听器的微结构优化设计

Microstructure Optimization Design of the MEMS Bionic Vector Hydrophone

压阻式的MEMS仿生矢量水听器的固有频率和灵敏度之间是相互制约的，即随微结构的各个尺寸（悬臂梁的长、宽、高及中心连接体的边长）的变化，二者呈现相反的趋势。通过理论分析和推导，得出每个尺寸对水听器固有频率和灵敏度的影响程度不一致，可以合理地设计微结构的各个尺寸（最优解），使矢量水听器在具有相同固有频率条件下得到最大灵敏度。根据常用的微结构，通过Matlab软件计算出了微结构的一组最优解。通过ANSYS软件仿真验证，与常用的微结构相比，该微结构固有频率下降了7％，而灵敏度提高了1倍。最后，测试结果表明：两组尺寸的水听器频带范围为20～1000Hz，并且尺寸优化后的水听器比优化前的灵敏度平均高5dB。

The relationship between inherent frequency and sensitivity of piezoresistive MEMS bionic vector is mutual restricted. The changing tendency of inherent frequency and sensitivity with the microstructure sizes （the length, width and height of the cantilever beam and the side length of the center connection body） is opposite. Through theoretical analysis and deduction, the effects of each size on the inherent frequency and sensitivity of the hydrophone are different, so the microstructure sizes （optimal solutions） are designed reasonably to obtain a maximum sen- sitivity for the vector hydrophone at the same inherent frequency. According to the commonly used microstructure, a group of optimal solutions of the microstructure were calculated by using Matlab software. Through simulation and verification of ANSYS software, compared with the commonly used microstructure, the inherent frequency of the microstructure decreases by 7%, but the sensitivity is doubled. Finally, the test results show that the frequency band ranges of thehydrophones with two groups of different dimensions are from 20 Hz to 1000 Hz, and the sensi- tivity of the optimized hydrophone is averagely 5 dB higher than that of the previous one.