Directional acoustic response of a silicon disc-based microelectromechanical systems structure

• Published in: Micro & nano letters 2014-04, Vol.9 (4), p.276-279
• Main Authors: Mackie, David James, Jackson, Joseph Curt, Brown, James Gordon, Uttamchandani, Deepak, Windmill, James Frederick Charles
• Format: Article
• Language: English
• Subjects: Acoustics; Beams (radiation); central suspension beam; circular discs; directional acoustic response; directional acoustical sensor; directional hearing organ; Discs; Disks; Doppler measurement; elemental semiconductors; finite element analysis; finite element modelling; Joining; laser Doppler vibrometry; measurement by laser beam; mechanical acoustic directionality analysis; MEMS microphones; MEMS‐based structure; Microelectromechanical systems; microfabrication; microphones; microsensors; modal analysis; Nanostructure; Ormia ochracea; parasitoid fly; relative vibration amplitudes; silicon; silicon disc‐based microelectromechanical systems; SOIMUMPS foundry process; Vibration
• ISSN: 1750-0443; 1750-0443
• DOI: 10.1049/mnl.2013.0677

A microelectromechanical systems (MEMS)-based structure capable of operating mechanically as a directional acoustical sensor is presented. The structure, fabricated through the commercially available SOIMUMPS foundry process, consists of two circular discs attached to a central suspension beam, fixed at both ends. The design of the structure resembles other directional MEMS microphones that mimic the directional hearing organ of the parasitoid fly, Ormia ochracea. Modal analysis and mechanical acoustic directionality analysis using both laser Doppler vibrometry and finite element modelling have been implemented. It is demonstrated that this coupled MEMS structure exhibits an acoustic directional response, with a one-to-one relationship between the relative vibration amplitudes of the two coupled discs and the angle of sound, from −75° to +60°.