Biomimetic MEMS directional microphone structures for multi-band operation

Researchers have developed a variety of micro-electromechinical systems (MEMS) directional microphones inspired by the behavior of the hearing organ of the parasitoid fly Ormia ochracea. Ormia´s hearing organ can detect a sound´s direction as accurately as the human auditory system despite its small overall size of less than 1mm. This remarkable capability has led to in-depth studies of its mechanics which, in turn, have led to the practical realization of several MEMS based directional acoustic sensors. The majority of earlier designs were limited to one frequency band and have relatively complicated structures for manufacture. A new MEMS microphone design described in this paper expands the simultaneous working frequency bands and reduces the cost of device fabrication without significantly increasing overall dimensions.