“反射面天線與焦面場分析”一般性科技報告

彭勃++金乘進++伍洋

摘 要：SKA的反射面天線覆蓋約300 MHz～20 GHz頻率范圍，寬帶單波束饋源和大視場相位陣饋源的使用將有可能對SKA天線的技術方案和綜合性能的提高起到重要的作用。該研究擬研究用于SKA反射面天線的寬帶單波束饋源和相位陣饋源。SKA的寬帶單波束饋源（WBSPF）分兩個波段，低頻段覆蓋約300 MHz～2 GHz，高頻段覆蓋1.6～10 GHz。課題組目前負責牽頭研究寬帶單波束饋源中的低頻段饋源的研制工作。該課題將研究基于Eleven Feed和Quad-Ridged Flared Horn兩種技術的寬帶饋源，低噪聲放大器和制冷技術方案。寬帶單波束饋源技術也可應用于大口徑射電望遠鏡。該研究還將研究用于大口徑射電望遠鏡的相位陣饋源技術，用于提升大口徑望遠鏡的總體性能，如提高巡天效率和單波束增益，開展電指向觀測等靈活的觀察模式試驗。該技術報告主要介紹幾類反射面天線的焦面場的仿真分析，和饋源設計中的焦面場共軛匹配的設計原則。這些焦面場的分析為饋源設計提供了重要的技術輸入。

關鍵詞：平方公里陣 射電天文 焦面場 相位陣饋源 寬帶單波束饋源

Report on “Focal Field Distribution Analysis for Reflector Antenna”

Peng Bo1 Jin Chengjin1 Wu Yang2

（1.National Astronomical Observatories， Chinese Academy of Sciences； 2.The 54th Research Institute of China Electronics Technology Group Corporation）

Abstract：The SKA dish will cover frequencies from about 300MHz～20GHz. 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 band 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.

Key Words：Square kilometre array； Radio astronomy； Focal field distribution； Phased array feed； Wideband single pixel feed