A 2D acoustic particle velocity sensor with perfectly orthogonal sensitivity directions

A two-dimensional acoustic particle velocity sensor as well as the required interfacing electronics have been designed and realized. The novel crossed-wire sensor structure provides a direct two-dimensional measurement and, contrary to current 2D particle velocity sensors, the sensitive directions are exactly orthogonal to each other due to the inherent symmetry of the sensor. This new design of size 1.0 mm × 2.5 mm × 0.5 mm dissipates only half the power required by current one-dimensional particle velocity sensors, has comparable bandwidth at modest 15 dB higher selfnoise. Furthermore, it requires no directivity calibration, which was difficult to achieve in previous designs. The devices are relatively easy to fabricate, smaller and mechanically more robust than existing parallel-wire particle velocity sensors, resulting in better resistance against harsh fabrication steps and, consequently, higher fabrication yield.