平面正弦天线及其小型化馈电巴伦

研制一款工作频段为3～15GHz的两臂平面正弦天线，使用50Q同轴电缆馈电。正弦天线具有平衡辐射结构及超宽带特性，因此必须使用相应的馈电巴伦进行匹配转换。但传统的指数渐变微带巴伦纵向尺寸过大，通常为0．5λmax不利于整个天馈系统的紧凑布置。因此，设计了一种小型化的微带馈电巴伦并用于两臂平面正弦天线的馈电。通过测试比较发现，在其各项性能和常规微带馈电巴伦的正弦天线基本保持一致的前提下，纵向尺寸得到了很好的压缩，利于实现紧凑布置。

A Planar Sinuous Antenna and the Miniature Balun

In this paper, a two-arm sinuous antenna fed by 50 Ω coaxial-cable for 3 - 15 GHz operation is presented. To match the balance structure and the wideband character of the antenna, its matched balun is inevitable. For the traditional microstrip balun is line-parallel wire which is exponentially gradual type, its vertical size is too large, usually about 0.5λmax . In order to reduce the total size of the antenna system, a miniature microstrip balun is designed to feed the antenna. Test results show that the sinuous antenna with miniature balun presents good performance over the whole frequency range and keeps good agreement with the original antenna.