A time-domain broadband acoustic carpet-type invisibility cloak and method of making the same

Abstract

The invention belongs to the technical field of acoustics, and in particular relates to a time-domain broadband acoustic carpet-type invisibility cloak and a manufacturing method. By combining a broadband sound pressure local reflection theorem and a parameter optimization method, a multi-layer air square hole stacking The structure of the metasurface is the basic structural unit of the metasurface, and a time-domain broadband metasurface structure is designed by using genetic algorithm reverse optimization; Stealth, its relative bandwidth has reached more than 93%, and at the same time, it exhibits the stealth performance of time-domain broadband under the incidence of multi-frequency pulses, breaking the limitation of narrow bandwidth of traditional passive metasurfaces and the defects of tunable metasurfaces time-domain broadband. The structural design of acoustic metasurfaces and the practical application of broadband acoustic devices provide a key research basis.

Description

technical field [0001] The invention belongs to the technical field of acoustics, and in particular relates to a time-domain broadband acoustic carpet-type invisibility cloak and a manufacturing method. Background technique [0002] In recent years, acoustic metamaterials have demonstrated a unique ability to manipulate sound waves. As a two-dimensional planarization of acoustic metamaterials, the thickness of the acoustic metasurface is controlled within the sub-wavelength scale, and the phase and amplitude of the acoustic wave can be arbitrarily regulated only by the gradient arrangement of one layer of microstructure units, thereby Achieving the goal of controlling large wavelengths with small size, breaking the limitation of large size of bulk acoustic metamaterials. [0003] The regulation of acoustic waves by acoustic metasurfaces is usually based on the generalized Snell's theorem, which controls the propagation direction of acoustic waves by setting the phase distri...

AI Technical Summary

Problems solved by technology

However, since the phase that the cloak needs to adjust changes with the incident frequency, the cloak made of metasurface can only work in a narrow target frequency range. The bandwidth is only about 7% to 36%

In addition, although there is an adjustable or reconfigurable way to broaden the operating frequency range of the metasurface cloak, but because the metasurface requires different geometric configurations at different frequencies, this cloak Under the incident of a multi-frequency pulse sound wave, it is still impossible to achieve time-domain broadband invisibility, but the time-domain broadband invisibility cloak can better hide objects from being discovered by the outside world

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