An L-Shaped 2-Dimensional Particle Velocity Sensor

An L-shaped two-dimensional acoustic particle velocity sensor (APVS), which has integrated two best performing one-dimensional APVS on a single chip is presented. This structure keeps the two sensitive axes exactly orthogonal to each other, avoiding the alignment error. There are no silicon substrate blocking in both sensitive directions, so the flow directions nearby the wires have little differences. As a result, the two axes have equal sensitivity, thus requiring no correction. The measured velocity sensitivity at 1 kHz is 2.53 dB V/Pa, with relative direction sensitivity of 28 dB. Since the total size of the chip is only 4.4 × 4.4 mm, it can detect the 2-D particle velocity at one point.