Design and Fabrication of Hollow Mushroom-Like Cilia MEMS Vector Hydrophone

Abstract

Vector hydrophone is the core equipment of underwater acoustic detection. Aiming at the problem of low sensitivity and short detection distance of existing vector hydrophone. In this paper, a hollow mushroom-like cilia sensitive structure is designed to optimize the hydrophone sensitive unit. The optimal size of the hollow mushroom-like cilia MEMS vector hydrophone (MCVH) microstructure was determined by COMSOL5.6 simulation. The hollow structure is adopted, which not only ensures the working bandwidth of the hydrophone is 20Hz-1000Hz, but also improves the sensitivity of the hydrophone by increasing the receiving area of the sound wave. The test results show that the hollow structure has obvious "8" directivity, and the pit depth of the "8" directivity larger than 40dB at 315Hz. Meantime, the sensitivity of MCVH can reach -180.9dB at 1000Hz. Compared with Ciliary MEMS vector hydrophone(CVH), the sensitivity is improved by 16.8dB.