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

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/mu Pa), 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 degrees. 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. Detecting submarines via biomimicry Jellyfish sensory organs offer the inspiration for a new sensor design that can sensitively detect low-frequency sounds underwater. These capabilities are particularly for the long-range detection of submarines, which produce faint sound signatures in the 5-200 Hertz range. Researchers have struggled to develop compact 'hydrophone' devices that can sensitively capture such frequencies underwater, but Wendong Zhang of the North University of China and colleagues have identified a promising solution. Modeled on the pectis jellyfish auditory organ, this system features an otolith-like structure mounted on a cross-beam that produces a piezoresisitive signal in response to vibrations. Based on this concept, the researchers fabricated a device that effectively detects very faint sounds in the 20-200 Hertz range at depths of at least 1000 meters, highlighting the potential of such 'otolith-inspired MEMS vector hydrophone' devices.

Automated summary

Inspired by the auditory organs of pectis jellyfish, a new sensor design for sensitive detection of low-frequency underwater sounds has been developed, with high sensitivity and shock resistance. This sensor is promising for long-range detection of submarines in the 20-200 Hz frequency range.