基于人工复合材料的新型隐身天线罩的研究

The goal of this project is to use the invisible radome comprising of artificial composite materials (Metamaterials, or metasurface) to achieve the stealth and electromagnetic protection for antenna which can radiate electromagnetic wave. Compared with ordinary absorbing materials, artificial composite materials can achieve ultra-thin and ultra-wideband absorption. By utilizing the 3D frequency selective surfaces, the sharp roll-off is achieved, which is of great significance for the effective exploit of electromagnetic spectrum, as well as to provide a chance to solve the coupling between the absorption band and the pass-band nearby. The theoretical research and technology of miniaturizing unit cell can resolve the angular stability of both transmission and absorption, leading to the feasible design of the non-planar radome. Finally, the method, by adding active components in artificial composite materials to achieve artificial magnetic material, can achieve the in-band stealth for antenna which is idle. This research of invisible radome to cloaking antenna not only involves the basic theory of artificial composite materials, but also addresses the practical problems during engineering, which is of both theoretical and practical significance. As its applications can service both the military and the civilian, the project is worth studying.

本项目主要研究利用人工复合材料（即超材料或超颖表面材料）制作天线罩来实现天线这种带有辐射源结构的电磁隐身与电磁防护。与普通吸波材料相比，人工复合材料能够实现超薄、超宽带吸收；通过3d频率选择表面来实现天线工作频段的电磁波陡峭式传输，可以节约电磁频谱的带宽资源，同时为解决隐身天线罩中吸收频带与传输频带相近时的互扰问题提供了可能。通过单元尺寸小型化理论与技术的研究，实现人工复合材料电磁特性（传输与吸收）的角度稳定性，进而研究三维曲面天线罩的相关设计问题。最后通过在人工复合材料中加入有源元器件来实现人工磁性材料，实现天线非工作状态下的带内隐身。这种隐身天线罩的研究不仅涉及到人工复合材料的基本理论，还将解决隐身天线罩工程化涉及的很多实际问题，其研究兼具理论和工程意义；其应用领域涉及军队和民用，因此具有较大的研究价值。

本项目主要研究隐身天线罩所涉及的基本理论及其设计方法，通过多单元级联等方式设计频率选择表面，实现电磁波的陡峭式传输来解决隐身天线罩中吸收频带与传输频带相隔较近时的互相干扰问题；通过集总电阻或分布式电阻（电阻膜）加载人工复合材料及超颖表面材料来实现带外的超宽频带电磁吸收，设计了高脚杯、窗型、柠檬结构、单双六边形及组合单元等不同形式的隐身天线罩，实现了常用工作频带的低损耗传输和其余频段（包含双侧吸收）的宽带吸收效果；构建合适的等效电路分析法，加速单双环结构的隐身天线罩设计；重点研究了圆柱这种可展开和球形不可展开曲面的隐身天线罩的设计及加工方法，设计一种平面和球面的单元映射关系，简化了三维非可展开曲面吸波体的设计流程。上述的设计进行了样品加工，设计方法和性能得到了实验验证。项目的研究成果在一定程度上拓展了基于人工复合材料隐身天线罩的应用前景。