【摘要】：聲學(xué)超材料,是一種用于操縱聲波的人工聲學(xué)結(jié)構(gòu),具有諸多自然界所不具備的超常物理性質(zhì).不同于早期的局域共振聲學(xué)單元結(jié)構(gòu),基于希爾伯特分形曲線提出了一種具有低損耗、高折射率的分形聲學(xué)超材料,給出了分形結(jié)構(gòu)聲學(xué)單元的進(jìn)化過(guò)程,并運(yùn)用等效媒質(zhì)理論,提取了具有亞波長(zhǎng)的分形超材料單元的相對(duì)折射率、相對(duì)阻抗、等效密度及等效模量等材料參數(shù).由于分形結(jié)構(gòu)具有的自相似性和空間折疊特性,所提出的分形超材料具有寬帶工作頻率響應(yīng),為眾多應(yīng)用場(chǎng)合比如聲超分辨率成像及聲隧穿效應(yīng)器件提供了候選材料.為檢驗(yàn)分形聲學(xué)超材料特性,應(yīng)用分形聲學(xué)超材料設(shè)計(jì)了梯度折射率分布的聲聚焦透鏡,并由固體方塊陣列仿真對(duì)比、實(shí)驗(yàn)測(cè)量、以及點(diǎn)聲源入射等三種手段驗(yàn)證了分形聲學(xué)超材料參數(shù)特性及其聚焦透鏡在2~5kHz寬頻帶內(nèi)良好的聚焦能力.
[Abstract]:Acoustic metamaterial is an artificial acoustic structure used to manipulate sound waves, which has many unusual physical properties that nature does not possess. Unlike the early local resonance acoustic unit structure, a fractal acoustic metamaterial with low loss and high refractive index is proposed based on Hilbert fractal curve, and a fractal structure acoustic monolayer is given. The relative refractive index, relative impedance, equivalent density and equivalent modulus of the fractal metamaterials with sub-wavelength are extracted by using the theory of equivalent medium. In order to test the properties of fractal acoustic metamaterials, the acoustic focusing lens with gradient refractive index distribution is designed by using fractal acoustic metamaterials. The fractal is verified by solid block array simulation, experimental measurement and point source incidence. Acoustic characteristics of metamaterial and its focusing ability of focusing lens in 2~5kHz broadband.
【作者單位】： 東南大學(xué)毫米波國(guó)家重點(diǎn)實(shí)驗(yàn)室;北方信息控制集團(tuán)有限公司;
【基金】：國(guó)家自然科學(xué)基金(61571117;61138001;61171024;61171026)
【分類(lèi)號(hào)】：TB51

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