Novel Electret Microphone

Author

Bakhoum, Ezzat G. ; Cheng, Marvin H M

Author_Institution

Dept. of Electr. & Comput. Eng., Univ. of West Florida, Pensacola, FL, USA

Volume

11

Issue

4

fYear

2011

fDate

4/1/2011 12:00:00 AM

Firstpage

988

Lastpage

994

Abstract

This paper introduces a new type of electret microphone with an excellent dynamic range (0-120 dB SPL) and excellent frequency response characteristics over the range of 20 Hz to 20 kHz. The fundamental concept behind the new microphone is the placement of a thin PTFE (Teflon) electret membrane inside the core of a toroidal coil. As the membrane vibrates in response to the sound, a very small magnetic field is created, is picked up by the coil, and is amplified by a superconducting quantum interference device (SQUID) or by a conventional FET amplifier. Analysis and experimental results show that this new transduction mechanism results in a microphone that, while physically larger than other microphones, has substantially better performance in high-bandwidth applications.

Keywords

SQUIDs; electrets; field effect transistors; microphones; polymers; FET amplifier; PTFE electret membrane; electret microphone; frequency response characteristics; high bandwidth application; superconducting quantum interference device; toroidal coil; transduction mechanism; Acoustics; electret microphone; magnetic field sensor; microphone; vibrations;

fLanguage

English

Journal_Title

Sensors Journal, IEEE

Publisher

ieee

ISSN

1530-437X

Type

jour

DOI

10.1109/JSEN.2010.2077276

Filename

5585649