A Microformed Magnet-Based Microphone/Speaker Array for Active Noise Reduction

Research Support Instruments, Inc. (RSI) proposes to develop a MEMS microspeaker/ microphone array for use in active noise reduction (ANR). Micromachined pressure transducers using piezoresistive or capacitive sensing techniques are well developed; this project will instead develop a magnetic microphone. Magnet-based microphones in macroscale technologies have advantages in sensitivity, bandwidth, and ruggedness; similar advantages can be expected on the microscale. The same technology will be used to develop a microspeaker. RSI has an innovative technology to develop micromagnets; using micromagnets in both the microphones and the speakers will ease integration of the two circuits, and take advantage of both technologies. The Phase I program will involve design, fabrication, and test of magnet-based MEMS microphones and speakers to determine their sensitivity, speaker amplitude, ruggedness, and bandwidth. RSI will use its experience in silicon nitride membranes, micromagnets, and pressure sensors to employ a highly innovative microfabricated technology - the magnetic MEMS speaker/microphone array - in order to develop speakers and microphones with a combination of sensitivity and speaker amplitude previously unattained by MEMS-sized devices.