Three-hot-wire acoustic particle velocity sensor with improved detection capability

This Letter proposes a novel 3-hot-wire acoustic particle velocity sensor with high sensitivity and low self-noise for the first time. Three parallel wires, covered with platinum film, are suspended on silicon substrate by MEMS process. The middle wire works as a heater and the left and right ones work as both heaters and temperature sensors. Compared with the 1-hot-wire and 2-hot-wire counterparts, this sensor has higher sensitivity and lower self-noise, showing its potential for sound source localisation, acoustic camera and so on. The self-noise of the sensor is about $15\, {\rm dB}/\sqrt {{\rm Hz}} $15dB/Hz at 1 kHz and the relative direction sensitivity is as high as 42 dB.