Design and implementation of two-component cilia cylinder MEMS vector hydrophone

Abstract

In previous studies of MEMS vector hydrophone, the ideas of increasing the sound signal reception area were only considered for improving the sensitivity of cilium MEMS vector hydrophone (CVH), which lead to a problem of increasing the load of cantilever beam. In order to solve the problem, a two-component cilia cylinder MEMS vector hydrophone (TCVH) is developed in this paper. TCVH can improve the sensitivity of MEMS vector hydrophone with the same load of cantilever beam as CVH. Firstly, device structure parameters of the two-component cilia cylinder and cross-beam are determined based on the theoretical analysis and simulation analysis. Compared with the modal shapes of CVH, the overall structure of TCVH is more stable. And in terms of fabrication, the secondary integration process become more simple than that of previous works due to the consistency of the upper and lower cilia materials as well as the feature of no mould. Then, the results of the standing waves field comparison calibration test show that compared with CVH, the sensitivity of TCVH is increased by 4.5 dB on the condition of same load on cantilever beam in the range of 20–1000 Hz. In addition, the sensitivity of an optimized dimension structure can be increased by 8.3 dB, reaching up to −188.1 dB (1KHz 0 dB at 1 V/μPa). Finally, the “8” shape directivity and concave point depth (>30 dB) demonstrate that the TCVH has a good target detection capability.