低轮廓高效率的印刷复合空馈阵天线

Low-profile and high-efficiency printed compound air-fed array antenna

印刷式复合空馈阵是一种融合印刷反射阵和传输阵概念为一体的新型天线,具有馈电简单、效率高、轮廓低、成本低等特点。研究了两种提高该类天线效率的技术:采用基板和盖板上印刷尺寸渐变的贴片进行相位补偿,使天线口径面的场分布趋于同相;并采用"蘑菇型"人工磁导体表面作为基板以抑制横向波,以减小副瓣和交叉极化,由此提高了天线增益。设计工作于14 GHz的天线样机的测试结果与仿真结果吻合,达到近20 dBi的峰值增益,对应82%的口径效率,以及增益跌落少于3dB且回波损失低于-10 dB的8.4%公共频带;天线的剖面总高度仅为12 mm,即0.560λ。

The printed compound air-fed array is a novel structure of antenna which combines the concepts of printed reflectarray and transmitarray, exhibiting distinct advantages such as simple feeding structure, high efficiency, low profile and low cost. Two key techniques for enhancing its efficiency are developed in this article. Firstly, by using tapered patches on the cover and inversely tapered patches on the base to compensate phase difference resulted from different ray-length, and then to unify the phase distribution over the antenna aperture; secondly, by adopting ＂mushroom＂ type of artificial magnetic conductor surface as base to suppress the lateral waves within base and cover for enhancing the performance of side-lobe level and cross-polarization. An antenna prototype is designed, fabricated and measured. The measured results are in good agreement with simulated ones, obtaining nearly 20 dBi peak gain corresponding to 82 % aperture efficiency, 8.4 % common bandwidth for both gain-drop≤3 dB and return-loss≤-10 dB. The total height of profile is only 12 mm, i.e. 0.56λ0.