Characterization of Bio-Inspired Mems Underwater Acoustic Sensor Using a Standing Wave Tube
Abstract
NPS has developed MEMS-based underwater sensors based on the auditory structure of the fly Ormia ochracea. The sensor produces an output signal based on sound interacting with two mechanically coupled wings attached to a substrate using two torsional legs. The MEMS sensor operates at a resonance frequency determined by the geometrical structure. This thesis discusses the characterization of a water-filled standing wave tube, which is a device that is commonly used to characteristic directional acoustic sensors. The standing wave tube generates a plane wave along its axis and provides a convenient way to characterize the directional response of MEMS sensors for underwater applications. Two MEMS sensors were tested with simulated resonance frequencies of 450 Hz and 640 Hz, respectively. The MEMS sensors operate similarly to pressure-gradient microphone and are expected to exhibit an output signal dependent on the cosine of the incidence angle of sound. Both sensitivity and directionality measurements were taken in the standing wave tube using an underwater omnidirectional loudspeaker as a sound source. This research shows the standing wave tube is a viable testing device for MEMS sensor characterization, and the NPS-designed MEMS sensors for underwater applications clearly demonstrated characteristics of a directional acoustic sensor.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2022
- Accession Number
- AD1204808
Entities
People
- Patrick A. Celestine
Organizations
- Naval Postgraduate School