中文摘要：

超宽带馈源在通信和射电天文等领域有着极高的应用价值。四脊喇叭作为宽带馈源的一种重要形式，存在着反射损耗性能较差，方向图随频率波动严重，照明张角难以拓展等诸多缺陷。本文基于国际上已有的研究基础，设计了一款工作于1.2~6.8 GHz的双极化大张角四脊型超宽带馈源。该设计方案对脊片部件采用了“削出倒角”、“厚度赋形”和“脊片外延”的改进措施，显著改善了馈源在低频段的反射损耗性能，同时也拓展了照明张角，使其能够更好地应用在大张角主焦照明的场合。实测结果显示出，该超宽带馈源的带宽和反射损耗性能均略优于国外样机。在边缘照明角为68＆#176;的大张角情况下，该馈源依然可以在1.2~6.8 GHz的带宽（相对带宽5.67：1）内达到低于-10 dB的反射损耗，其中在2.5~5.3 GHz内的反射损耗低于-15 dB。而且，该馈源在E面和D面的-12 dB边缘照明角随频率的波动小于20＆#176;。

英文摘要：

Ultra-WideBand （UWB） feeds play critical roles in communications and radio astronomy. Quad-ridged horns in general have the performance of poor return loss, severe fluctuation with frequency of the beam patterns and relatively small illumination angle. Based on the latest developments, this paper proposes a dual-polarized large-subtended-angle quadruple-ridged UWB feed working from 1.2~6.8 GHz. By adopting “chamfering”,“profiled thickness” and “over-extension” to the ridge structure, the return loss at the lower frequency is significantly improved and the illumination angle is broadened to 68＆#176; so that it is more suitable for the primary-focus reflector systems. Measurements of the manufactured feed show that the bandwidth and return loss of this feed are slightly better than that of previously published foreign prototype in literature. With a large edge illumination angle of about 68＆#176;, the feed has a return loss of better than -10 dB from 1.2~6.8 GHz （the relative bandwidth is 5.67：1）, and even better than -15 dB from 2.5~5.3 GHz. The fluctuation of the edge illumination angles in E-plane and D-plane is less than 20＆#176; with an edge taper of-12 dB.