基于漫反射和随机编码理论提出一种应用于雷达散射截面积(RCS)缩减的超表面,并通过仿真和实验进行验证.首先,简要阐述了漫反射和随机编码理论,并设计一种基于金属分割线结构的线极化转换超单元.该结构基于"0"、"1"两种基本单元进行编码,在宽频段范围内实现180°反射相位差.仿真结果表明,超表面在6~14 GHz频段内,线极化转换率高达90%,RCS缩减大于10 dB的带宽达到6 GHz.然后,设计三种随机编码超表面,进行制备和实验测试.实验结果表明:在5.5~13 GHz频带范围内,三种随机超表面在垂直入射时的反射率小于-10 dB,存在6 GHz带宽RCS缩减大于10 dB,与仿真结果基本一致.另外,斜入射情况下,同样能得到有效的RCS缩减,随机编码超表面具备宽角度入射RCS缩减特性.该设计为雷达隐身技术提供了一种新的途径.%A kind of metasurface based on diffuse reflection and random coding theory was proposed, which could be used to reduce the radar cross section (RCS) reduction, and then simulation and experiments were performed to verify its properties. Firstly, the diffuse reflection and random coding theory were illustrated in briefly, and a linear polarization conversion super-cell based on metal cut-wire structure was designed. This structure could be applied in coded electromagnetic matrix by defining two basic units "0" and "1", respectively, which could achieve a 180° reflection phase difference in a broadband frequency range. The simulation results indicate that the linear polarization conversion rate of the designed structure is up to 90% in the frequency range of 6-14 GHz, and the bandwidth of over 10 dB RCS reduction is greater than 6 GHz. Then, three kinds of random coding metasurface samples were prepared and measured. The experimental results indicate that, in the frequency range of 5.5-13 GHz, the reflectance of the proposed three random coding metasurfaces are all less than -10 dB under normal incidence, and the average RCS reduction is greater than 10 dB, which are agreement reasonably with the simulations. In addition, a considerable RCS reduction was achieved in oblique incident case, which further verifies the excellent RCS reduction properties in a wide incident angle. The designs of random coding metasurface provide a new promising approach for the radar stealth technology.
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