Characterization of Micromachined Seesaw Type Microphone

A seesaw type microphone is characterized to study its feasibility for sound source localization. The microphone is composed of a flexible rectangular diaphragm sustained by two torsion-bars. With this structure, the microphone has two main dynamic modes: rocking mode from the twisting of the torsion bars and bending mode from the bending of the flexible diaphragm. Thus, the microphone’s motion is a combination of the two modes. Depending on the frequency of the incident sound and its arrival time difference at each side of the seesaw type microphone, relative motion of both sides of the seesaw type microphone is changed. By measuring relative amplitude and phase of the motion at each side of the microphone, arrival time difference of the sound source at each side can be estimated, and then, localization of the sound source is feasible. In this paper, we present that the microphone shows a significant vibration difference from each side when AC with 45° phase difference is applied to each side of the microphone to mimic the microphone receiving angled incoming sound.