Micromachined Microphones with In-Plane Directivity

date October 5, 2012
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Friday, October 5, 2012 4:00 p.m. in ETC 4.150

Michael Kuntzman
Department of Electrical and Computer Engineering
The University of Texas at Austin
http://www.ece.utexas.edu/
http://www.utmems.com/

Since being commercialized less than a decade ago, the microelectromechanical systems (MEMS) microphone market has seen dramatic growth, with 1 billion units shipped in 2011 and global shipments projected to reach 2.9 billion units in 2015. While low cost and robust, all current commercial MEMS microphones are omnidirectional. The signal-to-noise ratio (SNR) of MEMS microphones, while good enough for close-talking applications, is too poor to address advanced audio functionalities on the horizon. As a step towards realizing more innovative microphones that truly leverage unique design flexibility afforded by microfabrication, we will introduce piezoelectric microphones designed for in-plane figure-8 directivity. Topics will include description of the overall concept, microfabrication, and a presentation of directivity measurements on early proof-of-concept prototypes. A hybrid modeling method combining finite element analysis (FEA), modal analysis, and lumped element network modeling, which is capable of accounting for the dynamics of multiple vibration modes and multiple transduction ports, will be introduced.