An Axisymmetric Bionic Seal Whisker-Type Piezoelectric MEMS Vector Hydrophone

MEMS vector hydrophones are poised to become the core devices of miniaturized underwater acoustic sensing. However, existing MEMS vector hydrophones suffer from low sensitivity and shallow concave point depth, which hinders long-range detection. In this work, we present an axisymmetric bionic seal whisker–type piezoelectric MEMS vector hydrophone (ASWVH) that leverages bioinspired geometries and stress-concentration regions to amplify piezoelectric output, yielding enhanced directivity and high sensitivity. The optimal microstructure dimensions for ASWVH were determined using COMSOL 5.6 simulations. The biomimetic seal whisker structure not only ensures an operational frequency bandwidth of 20–2000 Hz but also expands the effective acoustic reception area, thereby further enhancing sensitivity. The unique wavy bionic sealing whisker shape provides high sensitivity, and the measured X-axis and Y-axis sensitivities are -171.7 dB and -173.2 dB@2 kHz (re. 1 V/μPa), respectively. Moreover, the device exhibits an exceptional “8”-shaped directivity pattern with concave point depth exceeding 40 dB in both channels, rendering it well-suited for high-precision passive underwater detection.