Aperiodic Sunflower-Like Metasurface for Diffusive Scattering and RCS Reduction
Aperiodic Sunflower-Like Metasurface for Diffusive Scattering and RCS Reduction
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DOI：
10.1109/lawp.2020.2980906
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发表时间：
2020-07-01
影响因子：
4.2
通讯作者：
Whittow, William G.
中科院分区：
文献类型：
--
作者：
Al-Nuaimi, Mustafa K. Taher;Hong, Wei;Whittow, William G.
这封信介绍了使用 Pancharatnam-Berry (PB) 元原子实现圆偏振 (CP) 波扩散和雷达截面 (RCS) 减小的非周期性向日葵状超表面的设计。 PB元原子在超表面孔径上的分布是不均匀的，并且具有受葵花籽启发的分布，即没有过渡周期性的向外对数螺旋晶格。所提出的超表面具有 600 个 PB 超原子，亚波长尺寸为 5 mm，近似于 0.33 lambda（20GHz），并表现出 0 度到 360 度之间随机选择的漫反射相位。模拟和实验结果都表明，当通常由 16 至 23.8 GHz 之间 RCS 衰减 > 7 的 CP 波照射时，所提出的向日葵状超表面可以有效地将反向散射能量扩散到多个方向。此外，在高达 60 度的倾斜入射下，可以保留低水平的漫散射。由于使用了这种 PB 概念，所提出的超表面的偏振敏感性被释放，这在入射波的偏振未知时的应用中是非常需要的。
This letter presents the design of aperiodic sunflower-like metasurface for circularly polarized (CP) wave diffusion and radar cross-section (RCS) reduction using Pancharatnam-Berry (PB) meta-atoms. The distribution of the PB meta-atoms across the metasurface aperture is nonuniform and has a distribution inspired by sunflower seeds, i.e., an outwardly logarithmic spiral lattice with no transitional periodicity. The proposed metasurface has 600 PB meta-atoms of subwavelength size of 5 mm approximate to 0.33 lambda(20GHz) and exhibits a randomly chosen diffusive reflection phase between 0 degrees and 360 degrees. Both simulated and experimental results demonstrate that the proposed sunflower-like metasurface can efficiently diffuse the backscattered energy into numerous directions when normally illuminated by a CP wave with RCS reduction > 7 between 16 and 23.8 GHz. Furthermore, the low-level diffuse scattering can be preserved under oblique incidence up to 60 degrees. As a result of using this PB concept, the polarization sensitivity of the proposed metasurface is released, and this is highly desired in applications when the polarization of the incoming wave is unknown.