Abstract: Acoustic hyperbolic metamaterials are artificial materials with hyperbolic dispersion characteristics and strong anisotropy. Their negative refractive properties are the theoretical basis for studying the implementation of high-resolution focused superlenses. In response to the problem that the recognition of far-field noise sources is limited by the resolution of 0.5 times wavelength acoustic Rayleigh diffraction recognition, combined with the excellent control effect of acoustic metamaterials on sound waves, a hyperbolic metamaterial that can achieve sub wavelength super-resolution imaging is introduced, and its negative refractive characteristics are used to design an acoustic hyperbolic structure for working at a frequency of 2 271.5 Hz. The dispersion and negative refraction characteristics of the hyperbolic structure of this configuration were analyzed, and the results show that, the group velocity direction of sound waves propagating in this hyperbolic metamaterial is perpendicular to the wave vector and follows the normal direction of the dispersion curve. The research in this paper provides some design references for realizing arbitrary regulation of sound wave and elastic wave, as well as focusing, locating, identifying and amplifying noise sources.

Key words: acoustic metamaterial, acoustic lens, elastic wave bandgap characteristic, negative refraction, hyperbolic dispersion, acoustic focusing