一層隨機(jī)分布的異向材料小橢球粒子的極化散射特征
Polarimetric Scattering from a Layer of Random Metamaterial Small Spheroids
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摘要: 該文推導(dǎo)了異向材料(Metamaterial)小橢球粒子的復(fù)散射振幅函數(shù)。構(gòu)造了一層隨機(jī)取向的異向材料小橢球粒子全極化散射的Mueller矩陣解。計算和比較了異向材料粒子和通常介質(zhì)粒子的散射特性、同極化后向散射系數(shù)hh, vv， 以及hh－vv 隨頻率的變化。計算了任一橢圓極化入射下一層非均勻取向的隨機(jī)分布異向材料粒子的同極化和交叉極化后向散射系數(shù)，以及隨機(jī)粒子產(chǎn)生散射場去極化的極化度。解釋了異向材料的媒質(zhì)參數(shù)對粒子散射特性的影響和一層粒子的散射機(jī)理。結(jié)果表明：與通常介質(zhì)粒子比較，異向材料粒子的散射產(chǎn)生了特征方向性的增強(qiáng)，全極化散射呈現(xiàn)非對稱模式，并且由于異向材料的 和與頻率的特殊關(guān)系，一層異向材料粒子的hh－vv 隨頻率有顯著的復(fù)雜變化。
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關(guān)鍵詞:
- 異向材料;極化散射;Mueller矩陣;色散
Abstract: In this paper the complex scattering amplitude functions of a small metamaterial spheroid particle is derived. The Mueller matrix for polarimetric bistatic scattering from a layer of random metamaterial small spheroids, such as dishes or needles, is constructed. Bistatic scattering of metamaterial and dielectric spheroids are numerically calculated. Linearly co-polarized backscattering coefficients hh, vv , and hh－vv are presented to show the dependence upon frequency. The co-polarized and cross-polarized backscattering coefficients and polarizability of a layer of non-uniformly oriented metamaterial spheroids under illumination of an elliptic polarized plane wave are numerically simulated. Effects of metamaterial parameters on scattering pattern and scattering mechanism are interpreted. Numerical results indicate that scattering of metamaterial particles is enhanced largely and appears apparent directivity. Meanwhile, polarized difference of hh－vv strongly varies with frequency due to constitutive dispersion of () and (). -
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