Straight Bridge Beams with Centered Diaphragm (SBBCD) design for MEMS cochlear biomodel

Abstract

This paper presents the development of an artificial basilar membrane (ABM) in order to biologically mimic the performance of a cochlea in human auditory system. The developed ABM should operate in an audible frequency range of a normal human ear which is in between 20 Hz to 20000 Hz. Two microelectromechanical system (MEMS) cochlear biomodel design; Straight Bridge Beams (SBB) and Straight Bridge Beams with Centered Diaphragm (SBBCD), have been considered for ABM development. Comsol Multiphysics software is used to design ABM and simulate their performance in terms of resonant frequency and static capacitance. SBB MEMS cochlear biomodel was designed with the dimension of 0.5 μm thickness, 20 μm width and in a range of 275 μm to 7700 μm length. As for SBBCD MEMS cochlear biomodel, an additional circular diaphragm with a diameter size of 75 μm is introduced to the center of the beam length. The SBBCD MEMS cochlear biomodel gave better performance with 2.84 % - 49.47 % of resonant frequency reduction and 9.44 % - 141.95 % of static capacitance increment in comparison with SBB MEMS cochlear biomodel.