High-Fidelity Mechanically Coupled Differential Microphone

Physical Sciences : Electrical

Available for licensing


  • Neal Hall, Ph.D. , Electrical and Computer Engineering
  • Michael Kuntzman, Ph.D. , Knowles Corporation
  • Karen Kirk , Mechanical Engineering

Invention Description

A new microphone is described that is readily fabricated with silicon micro-machining techniques. The structure uses an innovative design to respond directionally to sound, potentially with very high fidelity and high signal-to-noise ratio.


  • This system can be micro-machined on silicon using less than 1mm^2 area. Compared to conventional directional microphones, this structure is much smaller and can take advantage of the economies of scale inherent of semiconductor processing, leading to very low device unit cost.
  • The unique structure of this system may also enable superior signal-to-noise performance in comparison to larger microphones. Further, the directionality may be maintained up to 20 kHz.
  • When compared to other MEMS types of microphones, this structure has a unique sensing scheme, which may be suitable for fabrication with post-CMOS MEMS fabrication processes.

Market potential/applications

The market for miniature microphones is $2.5B and continuing to grow. This is primarily due to the pervasive use of microphones in cellular phones and laptop computers. Systems integrators in these areas will benefit from innovative microphones. This innovation addresses directionality and high fidelity, two figures of merit becoming increasingly important in the aforementioned applications. Additional applications include use of hearing aids, speech recognition systems, special medical instrumentation including otoacoustic emission based hearing health diagnostic systems, and special instrumentation applications such as large audio arrays.

Development Stage

Proof of concept

IP Status