文中研究了一种基于超材料的L 频段倍频角锥喇叭馈源,将超材料结构加载到角锥喇叭内壁,得到了辐射特性优良的喇叭馈源。设计优化了一种金属“十字线”状超材料单元,该单元为三维结构,顶部为正交的金属长方体,中心通过金属长方体与喇叭内壁相连接,周期排列形成阻抗超表面。超材料结构在TE 模式和TM 模式呈现不同的波阻抗,在特定条件下可使喇叭内传播模式达到平衡混合,从而实现了波束等化和低交叉极化。仿真结果表明,在1. 35 GHz~2. 70 GHz 之间,馈源驻波小于1. 25,照射角为20°,交叉极化小于-18 dB,代入标准卡氏天线中计算,效率在60%以上,旁瓣在-16 dB 以下,与现有工程常用波纹喇叭和光壁赋形喇叭相比,电性能相当,但在加工难度、制作成本和体积重量方面,该超材料喇叭具有明显优势。

An octave L-band pyramid horn feed source based on metamaterials is studied. The horn feed with excellent radiation characteristics is obtained due to metamaterial structure onto the inner wall of pyramid horn. A metal ‘cross line’ shaped metamaterial unit is designed and optimized, which has a three-dimensional structure with an orthogonal metal rectangular prism at the top, connected to the inner wall of the horn through the metal rectangular prism at the center, and periodically arranged to form an impedance metasurface. Metamaterial structure exhibits different wave impedances in TE and TM modes, which can achieve balanced mixing of propagation modes within the horn under specific conditions, thereby achieving beam equalization and low cross polarization. Simulation results show that between 1. 35 GHz and 2. 70 GHz, the standing wave ratio of the feed source is less than 1. 25, the illumination angle is 20 °, and the cross polarization is less than -18 dB. Calculated using a standard Coriolis antenna, the efficiency is over 60%, and the sidelobes are below -16 dB. Compared with commonly used corrugated horn and smoothed horn in engineering, the electrical performance of the designed metamaterial horn is comparable. However, in terms of processing difficulty, production cost, and volume weight, the designed metamaterial horn has significant advantages.

TN82