Acoustic seminar | 24 November 2023

Acoustic warning systems are promising for the variety of applications such as life detection, city security and battlefield alert. Their growing popularity is associated with the absence of the blind area, wide detection range and low cost. However, the capabilities of the conventional acoustic warning systems are significantly limited by the microphone performance as well as hardly working in harsh outdoor environments (e.g., windy and rainy weather). In this work, we propose an acoustic warning system based on metamaterials shells and its sensor array system, capable of working in outdoor environment. The metamaterial shell allows to significantly enhance acoustic signals while suppress outdoor wind noise. In addition, the structure is made of a rigid material protecting the microphones from rain and mechanical damage. In particular, it was demonstrated that acoustic signals can be enhanced by 8 times at the working frequency region, while the wind noise is reduced by 10–20 dB in the low frequency range below 1000 Hz. Our outfield test proves that the acoustic detection system based on the proposed metamaterial allows to estimate the azimuth of the sound source located at the distances up to 800 meters, with the accuracy about 95% in the windy environment, which is unreachable for the equivalent system without using the metamaterial shells. This work demonstrates the enormous potential of metamaterials for the improvement of detection systems and opens the route for the development of next-level warning systems.