Improved Design for Enhanced Performance of a Large-subtended-angle Quadruple-ridged Ultra-wideband Feed
Dong Bin① Han Jin-lin① Shen Quan② Yu Jing-long① Pang Feng①③ Zou Lei②
①(National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China) ②(The 39th Research Institute of China Electronic Technology Group Corporation, Xi’an 710065, China) ③( University of Chinese Academy of Sciences, Beijing 100049, China)
Abstract：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° 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°, 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° with an edge taper of -12 dB.
2014, Vol. 36 
