“反射面天线与焦面场分析”一般性科技报告

Report on “Focal Field Distribution Analysis for Reflector Antenna”

SKA的反射面天线覆盖约300 MHz^20 GHz频率范围,宽带单波束馈源和大视场相位阵馈源的使用将有可能对SKA天线的技术方案和综合性能的提高起到重要的作用。该研究拟研究用于SKA反射面天线的宽带单波束馈源和相位阵馈源。SKA的宽带单波束馈源(WBSPF)分两个波段,低频段覆盖约300 MHz^2 GHz,高频段覆盖1.6~10 GHz。课题组目前负责牵头研究宽带单波束馈源中的低频段馈源的研制工作。该课题将研究基于Eleven Feed和Quad-Ridged Flared Horn两种技术的宽带馈源,低噪声放大器和制冷技术方案。宽带单波束馈源技术也可应用于大口径射电望远镜。该研究还将研究用于大口径射电望远镜的相位阵馈源技术,用于提升大口径望远镜的总体性能,如提高巡天效率和单波束增益,开展电指向观测等灵活的观察模式试验。该技术报告主要介绍几类反射面天线的焦面场的仿真分析,和馈源设计中的焦面场共轭匹配的设计原则。这些焦面场的分析为馈源设计提供了重要的技术输入。

The SKA dish will cover frequencies from about 300MHzN20GHz. Wideband Single Pixel Feed （WBSPF） and Phased Array Feed （PAF） may be used to improve the frequency coverage and survey speed of the SKA dishes. This purpose of this project is to study the WBSPF and PAF technologies. The WBSPF of SKA is divided into two band, the baud low covers about 300MHz-2GHz, and the band high 1.6-10GHz. The project team is now leading the study of the WBSPF band low. Eleven Feed and Quad-Ridged Flared Horn will be studies, together with LNA and the cooling technology. The WBSPF technology may also be applied to large single-dish radio telescopes. The project will also study phased array feed technology, which is to be applied to large single-dish radio telescope. The PAF may help to improve the survey speed and single pixel gain, and enable electrical pointing and other observing mode. This report presents simulations of the focal field distribution several kinds of reflector antennas. And the conjugate matching principle in feed design is also presented. These focal field distribution analysis provides an important input to the feed design.