快波与慢波天线辐射机理及其在平面漏波天线优化设计中的应用

A planar leaky-wave antenna is a kind of traveling-wave antenna with beam-scanning capability. It has advantages of simple structure, low profile, easy fabrication and narrow beam, and can be used in radar, wireless location, satellite communication, wireless power transmission, etc. Leaky-wave antennas are with fast-wave radiation, so it is difficult for them to scan to exactly endfire. On the other hand, a traveling-wave antenna with slow-wave radiation can produce a beam pointing at exactly endfire, but it does not have beam-scanning capability. In this project, we will investigate radiation mechanism of fast-wave and slow-wave antennas, and design one-dimensional and two-dimensional planar leaky-wave antennas with optimization. Based on composite right/left-handed metamaterial and periodic structures, we will study microstrip and substrate integrated waveguide leaky-wave antennas. With the complementation of the fast-wave and slow-wave radiations, we will design a one-dimensional leaky-wave antenna with a beam scanning from back-endfire to front-endfire, and a two-dimensional leaky-wave antenna with a beam scanning from broadside to horizontal plane. The difficulties in the research are: new wave-guiding structures with a capability of both fast-wave and slow-wave radiations, complementation and control of the fast-wave and slow-wave radiations, suppression of the band-gap in a periodic structure, and analyses of the propagation properties of the developed guiding structures. The research would be benefit to the development of fast-wave and slow-wave traveling-wave antennas, and to the improvement of the theory of guided waves.

平面漏波天线是一种波束可扫描的行波天线，具有结构简单、剖面低、加工易和波束窄等优点，可用于雷达、无线定位、卫星通信和无线能量传输等系统。漏波天线属于快波辐射天线，对端射方向的扫描比较困难；而慢波辐射天线则可辐射于端射方向，但不具有波束扫描功能。本项目将深入探讨慢波和快波天线辐射机理，优化设计新型一维和二维平面漏波天线。基于特异材料以及周期性导波结构，研究微带和基片集成波导等平面漏波天线，利用快波辐射和慢波辐射互补，扩大漏波天线波束扫描范围，实现一维漏波天线主波束从后向端射到前向端射无盲点扫描，以及二维漏波天线主波瓣从法向到水平面全覆盖扫描。研究难点有：可支持快波辐射与慢波辐射的新型导波结构，快波辐射与慢波辐射的控制与互补利用，周期性结构漏波天线中谱隙的消除，导波结构中传播特性的理论分析。这些研究对于发展慢波与快波天线、完善导波理论，是非常必要的，具有极大的学术价值和应用意义。

平面漏波天线是一种波束可扫描的行波天线，具有结构简单和波束窄等优点，可用于雷达、无线定位、卫星通信和无线能量传输等系统。微带天线和基片集成波导天线具有平面结构，并具有剖面低、成本低和加工易等优点。本项目对微带天线、基于慢波辐射和快波辐射的行波天线展开深入研究，取得系列成果。首先，我们发现对于一个在端射辐射的行波天线，如果采用渐变的孔径分布，可得到端射方向性比采用均匀空间分布的方向性要高，采用基片集成波导天线验证了这一发现，此外，我们还从数值上分析了端射最高方向性系数下最优化孔径分布，基于数值结果总结出最优化孔径分布下方向性系数的计算公式。其次，我们研究了通过在微带漏波天线的中心线上周期性地加载短路过孔，调节过孔的间距，使得由短路过孔引入的基模阻带刚好覆盖第一高阶模的漏波工作频段，这样就有效抑制了基模的传播，提高了第一高阶模的激励，从而提高微带漏波天线的工作效率。最后，我们对多种微带天线展开研究，以提高天线的带宽、增益及圆极化性能。基于该项目，本人以第一/通讯作者发表SCI收录论文12篇，其中包括8篇论文发表于天线领域的国际顶级学术期刊（IEEE Transactions on Antennas and Propagation），超额完成项目预期目标。这些研究对于发展漏波天线、端射天线和微带天线有重要的学术意义和应用价值。