Fabrication of a microelectromechanical directional sound sensor with electronic readout using comb fingers

By emulating the hearing organ of the Ormia ochracea fly, a microelectromechanical sound sensor was fabricated which is able to determine the direction of incident sound despite an overall size much smaller than the wavelength of interest. The sensor consists of two wings that are coupled in the middle and attached to the surrounding substrate by two legs. The design incorporated interdigitated comb fingers on the wings and the substrate which enables electrostatic (capacitive) readout. Measured electrical response showed a strong dependence on the direction of incident sound.