S波段宽带微带天线设计

Design of Broad Band Microstrip Antenna at S Band

摘要: 本文设计了一种S波段宽带微带天线。该天线由差分微带天线和宽带180˚相移功分器两部分组成。首先利用180˚宽带相移功分器将单馈端口转换成差分馈电端口，然后通过加空气层和在贴片上开双十字槽进行带宽扩展。由于采用了差分馈电结构，天线既扩展了工作带宽，又在带宽内实现了良好的辐射性能，例如交叉极化低、方向图对称且增益稳定。研制出的天线矩形贴片尺寸为45.5 mm × 35.4 mm (W × L)，天线高度为13.5 mm。测试结果表明天线在10 dB回波损耗上的带宽为2.5~3.5 GHz，约33.3%，带宽内方向图稳定，交叉极化在−20 dB以下。

Abstract: A broad band microstrip antenna is designed at S band in this paper. The antenna is composed of a differential-fed microstrip patch and a broad band 180˚-phase-shift power divider. The 180˚- phase-shift power divider converts the single feeding port to the differential feeding ports. Then, the bandwidth is broadened by adding air layer and cutting double cross slots on the patch. Due to the differential-feeding structure, the proposed antenna has not only the broad band characteristic, but also desirable good radiation performance during the bandwidth such as low cross-pola- rization, symmetric patterns and stable gain. The size of the designed antenna rectangular patch is 45.5 mm × 35.4 mm (W × L). The antenna height is 13.5 mm. The measured results show that an impedance bandwidth from 2.5 to 3.5 GHz, i.e., 33.3%, is achieved. The pattern is quite stable dur-ing the bandwidth. The cross-polarization is under −20 dB.