This paper presents a long-range active acoustic sensing method based on microwave vibration measurement. Conventional microphones suffer from severe performance degradation in long-distance sound acquisition due to acoustic energy attenuation and environmental interference, while laser-based solutions are limited by high cost and sensitivity to ambient conditions. To address these challenges, we propose an approach that employs a frequency-modulated continuous-wave (FMCW) radar system to measure the phase variations of reflected microwave signals, thereby estimating the minute vibrations of sound-producing objects and reconstructing the corresponding acoustic signals. The vibration measurement principle is derived in detail, and multiple experiments are conducted with sound sources placed up to 10 meters away. The results verify that the proposed method effectively acquires various types of sound signals at long range while maintaining robustness against environmental noise. This work demonstrates the feasibility of microwave-based acoustic sensing as a promising alternative to conventional methods for remote sound acquisition.

Acoustic sensing,frequency modulated continuous wave (FMCW) radar,microwave sensing,remote sound sensing,vibration measurement