A Microelectromechanics Based Artificial Cochlea (membac)

MEMS design and modelling based on resonant gate transistor for cochlear biomimetical application

“…The geometrical dimensions of the bridge gate can be manipulated in order to attain certain values of resonant frequency and quality factor. Basically, the sensitivity and frequency selectivity of bridge gate can be designed from its geometry, material properties and the medium viscosity that surrounds the bridge gate (Bachman et al 2006;Haronian and MacDonald 1995;White and Grosh 2002). An array of RGTs with different length of bridge gates, each can responds to different resonant frequency , imitating the spatial arrangement of frequency along the basilar membrane length in cochlea.…”

“…Energy dissipation within the micromachined bridge gate structure can be described by several damping mechanisms that depend on and air pressure conditions (Hall et al 2008;Li and Fang 2009;Rebeiz 2003). Air can be used to dampen the oscillation of the vibrating bridge gates and the mechanism is known as the squeeze-film damping or air damping (Haronian and MacDonald 1995). For a MEMS resonating structure vibrating in standard atmospheric pressure and temperature, the squeeze-film damping will dominate, particularly when the gap size between the structure and substrate is smaller compared to its width and length.…”

“…The membrane peaks at different places for different excitation frequencies, providing a tonotopic distribution of frequency. High frequencies are detected close to the base section while low frequencies at the apex partition of the basilar membrane The fact that the cochlea itself is an electromechanical acoustic transducer and the advanced development of micro-and nanofabrication technology have drawn researchers' attention to employ MEMS in cochlear model (Bachman et al 2006;Haronian and MacDonald 1995). An array of MEMS resonators for examples the cantilevers and bridges, each with a specific resonant frequency can perform the passive parallel spectral filtering in a similar manner with the BM.…”

“…An array of MEMS resonators for examples the cantilevers and bridges, each with a specific resonant frequency can perform the passive parallel spectral filtering in a similar manner with the BM. Haronian and MacDonald (1995) have demonstrated that a large array of silicon bridges with exponentially varying length possessed similar mechanical behaviour as the cochlea. Small spacing distance between the bridges caused the bridges to be coupled by the viscosity of air, mimicking the cochlea's travelling wave phenomenon.…”

Mechanism of an arched basilar membrane in mammalian cochlea

“…These challenges include fabrication and analysis of the microfluidic artificial cochlear, fabrication of the basilar membrane, study of the fluid mechanics in mammalian cochlea, impedance matching from the tympanic membrane (air) and the oval window (scala fluid). Three areas of research are focused in this work; the mechanism of a relatively constant width and thickness basilar membrane, the development of a bonding methodology for the thin basilar membrane and the development of an electric-acoustic transducer to match the air-to-scala fluid impedance.The frequency-mapping and sensitivity of the cochlea depend on the variation of dynamic structural properties of the basilar membrane as well as the properties of the OHC.Most of the artificial cochleas require a fish-bone structure[37] to enable a wide hearing range and frequency selectivity comparative to mammalian cochlea. This limits the size of the artificial cochlea as well as the use for other microfluidics applications.…”