A Compact Acoustic Particle Velocity Gradient Sensor Based on MEMS Hot-Wire Sensor Chips

A compact and superdirective particle velocity gradient (PVG) sensor based on two MEMS hot-wire acoustic particle velocity sensor (APVS) chips is proposed. The capability of directly measurement of second-order directionality of acoustic field makes the PVG sensors are more competitive than currently used acoustic vector sensors or microphone arrays, while the compact design can broaden their working frequency. With the APVS spacing of 3.6mm, the measured directional patterns are all cosine squared shape up to 5 kHz, which demonstrated the feasibility for directly acquirement of second-ordered directionality. The sensor could be monolithic integrated to further shorten the spacing of velocity sensors, and to be more competitive for high-sound-frequency and narrow-space directional acoustic sensing applications.