Enhanced broadband acoustic sensing in gradient coiled metamaterials

Enhanced acoustic sensing is a topic of interest in a variety of research fields. Here, we propose a gradient coiling up metamaterial (GCM), combining gradient and coiled structures, so as to realize enhanced broadband acoustic sensing. Compared with metamaterials without coiled structures, the GCM shows a far superior performance in terms of acoustic enhancement, enabling the acoustic signals to be magnified up to approximately 80 times, over a wide frequency range. Moreover, by virtue of coupling the coiled structures, trapped and enhanced frequencies in the GCM can be reduced by nearly 43%. In addition, we numerically and experimentally demonstrate the property of frequency-selective enhancement over a wide frequency range, which can be used to approximate unknown signals by changing their measured positions. Moreover, harmonic signals with useful information can be effectively recognized and recovered from strong background noise, using GCM. Our results indicate that GCMs can be regarded as a functional material or an enhanced acoustic sensing device to improve the acoustic sensing performance of signal detection in practical engineering applications.

Automated summary

The GCM proposed in this study combines gradient and coiled structures to achieve enhanced broadband acoustic sensing, with the ability to amplify acoustic signals up to approximately 80 times over a wide frequency range. By coupling coiled structures, trapped and enhanced frequencies in the GCM can be reduced by nearly 43%. Experimental results demonstrate that GCM can enhance frequency-selective unknown signals and effectively recognize and recover harmonic signals from strong background noise.