A Monolithic Integrated MEMS Acoustic Dyadic Sensor

An integrated acoustic dyadic sensor which can measure the particle velocity gradient of sound field is proposed. It can better reject unwanted sound signals than scalar sound pressure sensors and acoustic vector sensors thanks to its capability to measure higher order information of sound field. The spacing between two vector sensors is reduced into only 2 mm by using MEMS technology to integrated the vector sensors into a single chip. The measured beam patterns are nearly the same with the cosine squared shape up to 6 kHz, which shows the feasibility for obtaining the particle velocity gradient. It can be quite competitive for high frequency and narrow space directional acoustic sensing applications.