一种高增益低雷达散射截面的新型圆极化微带天线设计

设计了一种基于人工电磁材料覆层的高增益低雷达散射截面(radar cross section, RCS)圆极化微带天线. 人工电磁材料覆层是由介质板及其两侧的人工周期表面构成, 上表面是加载集总电阻的方环贴片, 具有宽带吸波特性; 下表面是开条带缝和圆环缝的金属贴片, 具有部分反射特性. 将其加载到圆极化微带天线上方, 通过覆层上表面的电阻可吸收入射的雷达波, 结合下表面与接地板构成Fabry-Perot谐振腔的多次反射, 可实现圆极化微带天线辐射和散射性能的同时改善. 实测结果表明: 加载人工电磁材料覆层后, 天线的相对轴比带宽由5.9%扩展为7.1%; 天线增益在整个工作频带内都得到了提升, 最大提高了6.61 dB; 天线RCS在宽频带宽角域内实现了明显的减缩, 在天线工作频带内也实现了3 dB以上减缩. 实测结果与仿真结果符合较好.

A novel circularly polarized patch antenna with low radar cross section and high-gain

A novel circularly polarized patch antenna, which can achieve low radar cross section (RCS) and high gain performance simultaneously, is designed on the basis of metamaterial superstrate. The novelty of the design is that this antenna can possess the absorbing characteristic and the partially reflective characteristic simultaneously in an integrated structure. The proposed superstrate is composed of two metallic layers with different periodic patterns on both sides of a dielectric substrate. Through constructing different metallic patterns on the two sides of the superstrate, the upper and bottom surfaces of the superstrate will have different transmission and reflection performances when illuminated by an incident plane wave. The low RCS characteristic is dependent on the upper surface, while the gain enhancement of the resonator antenna relies on the reflection coefficient of the bottom surface. The upper surface consisting of a periodic metallic square loop with four lumped resistances on the four sides of the loop is of low reflection and transmission, and the bottom surface composed of a metallic plane with periodic slots is of high reflection and low transmission. When the superstrate is located at approximately half a wavelength above the ground plane of the circularly polarized patch antenna, the upper surface will absorb most of the incident wave by converting the electromagnetic wave into heat as Ohm loss to reduce the antenna RCS, and the bottom surface will form a Fabry-Perot resonance cavity with the ground plane of the antenna to achieve high gain and high directivity by multiple reflections between the bottom surface and the ground plane. The measured results show that with using the superstrate, the relative axial ratio bandwidth of the circularly polarized patch antenna extends from 5.9% to 7.1%, and the high gain performance is achieved in the whole working frequency band, which can be enhanced by 6.61 dB at most. Meanwhile, the RCS of the proposed antenna is dramatically reduced in a wide angle range and a broad frequency band covering a range from 2 to 14 GHz. The measured results are in good agreement with the simulated ones, which further verifies the correctness and effectiveness of the proposed method.