A Structure-Optimized Acoustic Particle Velocity Sensor with Improved Sensitivity and Self-Noise

An acoustic particle velocity sensor with improved sensitivity and self-noise is presented, which provides significant guidance for practical applications requiring a high signal-to-noise ratio (SNR). The sensor features extremely long and thin wires (2000 μm × 2 μm) that are completely suspended. To eliminate alignment errors for thin wires and optimize the silicon frame, a modified micromachining process is proposed. As a result, the sensor achieves a high sensitivity of -21.9 dB V/Pa at 1 kHz and a minimum self-noise of $4.5{\text{dB}}/\sqrt {{\text{Hz}}} $ at 950 Hz.