A Compact Three-Dimensional Acoustic Vector Sensor with Stepped Double Semi-Cone Tube Horn

This paper introduces a compact MEMS three-dimensional orthogonal thermal acoustic vector sensor, featuring a novel stepped double semi-cone tube (Stepped-DSCT) acoustic horn structure. Compared to existing designs, this structure provides a larger and flatter sensitivity gain, while maintaining the coherence of the sensor's triaxial signals without increasing the structural size. Additionally, the enhanced packaging improves directivity depth, further boosting the directional performance of the three-dimensional acoustic vector sensor. This design provides a practical and advanced solution, achieving a balance between packaging size and gain performance, with significant implications for real-world engineering applications. Experimental results demonstrate that the sensor achieves a sensitivity gain of 12.5 dB and a directivity gain of 13 dB at 1 kHz.