Design and implementation of a jellyfish otolith-inspired MEMS vector hydrophone for low-frequency detection

TLDR

Detecting low‑frequency underwater acoustic signals can be a challenge for marine applications. The study develops an otolith‑inspired vector hydrophone (OVH) based on jellyfish auditory organs to detect low‑frequency underwater acoustic signals. The OVH design was optimized through parametric analysis of cilium structure, stress‑distribution simulations, shock‑resistance testing, and then fabricated and calibrated. The OVH achieved a receiving sensitivity of −202.1 dB@100 Hz, an average equivalent pressure sensitivity of −173.8 dB over 20–200 Hz, a 3 dB polar width of 87°, and operated under 10 MPa hydrostatic pressure, demonstrating its promise for low‑frequency underwater acoustic detection.

Abstract

Abstract Detecting low-frequency underwater acoustic signals can be a challenge for marine applications. Inspired by the notably strong response of the auditory organs of pectis jellyfish to ultralow frequencies, a kind of otolith-inspired vector hydrophone (OVH) is developed, enabled by hollow buoyant spheres atop cilia. Full parametric analysis is performed to optimize the cilium structure in order to balance the resonance frequency and sensitivity. After the structural parameters of the OVH are determined, the stress distributions of various vector hydrophones are simulated and analyzed. The shock resistance of the OVH is also investigated. Finally, the OVH is fabricated and calibrated. The receiving sensitivity of the OVH is measured to be as high as −202.1 dB@100 Hz (0 dB@1 V/μPa), and the average equivalent pressure sensitivity over the frequency range of interest of the OVH reaches −173.8 dB when the frequency ranges from 20 to 200 Hz. The 3 dB polar width of the directivity pattern for the OVH is measured as 87°. Moreover, the OVH is demonstrated to operate under 10 MPa hydrostatic pressure. These results show that the OVH is promising in low-frequency underwater acoustic detection.