Development of cup-shaped micro-electromechanical systems-based vector hydrophone

Abstract

Similar to the vital performance factors, the receiving sensitivity and the bandwidth exist interactively in the micro-electromechanical systems (MEMS)-based vector hydrophones. Some existing methods can improve the sensitivity of the hydrophone, but these improvements are usually gained at a cost of the bandwidth. However, the cup-shaped MEMS vector hydrophone that is presented in this paper can improve its sensitivity while retaining a sufficient bandwidth. The cup-shaped structure acts as a new sensing unit in the MEMS vector hydrophone, replacing the bionic columnar hair that was previously used for sensing. The relationships between the parameters of the cup-shaped structure and the sensitivity of the vector hydrophone were determined by a theoretical deduction. In addition, simulation analyses were performed, and optimized structural parameters were obtained in this work. ANSYS 15.0 simulation was used to derive the optimum characteristics for the cup-shaped structure. The results of the calibration experiments showed that the sensitivity reached up to −188.5 dB (gain of 40 dB, 1 kHz, 0 dB@1 V/μPa), and the bandwidth was in the 20 Hz–1 kHz range, which is sufficient for an underwater acoustic detection at low frequencies. This work has, thus, proved that the cup-shaped vector hydrophone has superior properties for the engineering applications.