Document Detail

Response of a MEMS (microelectromechanical systems) directional microphone diaphragm with active Q control.
MedLine Citation:
PMID:  20330832     Owner:  NLM     Status:  In-Data-Review    
Measured results are presented that demonstrate the use of proportional and derivative electronic feedback to improve the performance of a directional microphone. The microphone diaphragm consists of a 1 x 2 mm stiffened plate fabricated out of polycrystalline silicon that is supported on a central hinge. The sound pressure gradient incident on the diaphragm produces a rocking motion about the central hinge. Interdigitated comb fingers at each end of the diaphragm enable both capacitive sensing and electrostatic actuation. The sound pressure gradient near the diaphragm has been measured by numerically differentiating the pressure measured by a probe microphone at locations around the diaphragm. The sound-induced motion of the diaphragm was measured using a laser vibrometer. From these measurements, estimates of the mechanical parameters of the diaphragm were obtained. By applying a known quasi-static voltage across the interdigitated fingers and measuring the resulting diaphragm deflection, an estimate for the derivative of the capacitance with respect to the displacement is obtained for the comb fingers of the diaphragm. Using these experimentally determined parameters and a linearized dynamic model of the system, the measured response of the microphone system with feedback is accurately predicted. [Work funded by NIH Grant R01 DC009429.].
Quang T Su; Ronald N Miles; Weili Cui; Mihir Shetye; N Eva Wu
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of the Acoustical Society of America     Volume:  127     ISSN:  1520-8524     ISO Abbreviation:  J. Acoust. Soc. Am.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-24     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7503051     Medline TA:  J Acoust Soc Am     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1944     Citation Subset:  IM    
Dept. of Mech. Eng., Binghamton Univ., Binghamton, NY 13902-6000,, City of Industry, CA 91748Binghamton Univ., Binghamton, NY 13902-6000.
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