宽带波束固定漏波天线的机理研究及优化设计

Leaky-wave antennas have advantages of low cost, easy feeding, wide impedance bandwidth, narrow beamwidth and high gain. However, due to the inherent dispersions in the leaky-wave structures, the main beam of a leaky-wave antenna squints with frequency. In wireless communications, the spectrum in the radiation space is dispersed due to the beam squint, resulting in the loss of the integrity of the signal spectrum. This limits the applications of the antennas. Therefore, we will investigate the mechanisms in the dispersions, find ways to suppress the dispersions, and design beam-fixed (squint-free) leaky-wave antennas. In this program, (1) we will compensate the normal dispersions in the conventional leaky-wave structures using networks with abnormal dispersion or negative group velocity; (2) we will develop new fast-wave structures with no dispersion using non-Foster circuits and other techniques; (3) we will investigate the working principle in the superluminal structures with abnormal dispersion, negative group velocity or non-Foster property; (4) finally, we will make optimal designs of leaky-wave antennas that have a squint-free beam with high gain in wide band. The squint-free leaky-wave antennas can be applied to various wireless communication systems. The research is not only useful for solving the beam squint problems in travelling-wave antennas and antenna arrays, but also for solving the dispersion problems in circuit systems. Moreover, it is of great academic interest for the development of new wideband metamaterials, and for the electromagnetic theories in the superluminal structures.

漏波天线具有成本低、馈电容易、阻抗带宽大、波束窄和增益高的优点，但是由于漏波结构中的色散，其主波束方向往往会随频率而变化。在无线通信中，其辐射频谱在空间中会分散导致通信信号频谱不完整，致使漏波天线的应用范围受限。因此，我们将研究漏波结构中的色散机理及色散抑制方法（科学问题），以获得波束固定的漏波天线。本项目将：（1）研究负色散、负群速电路补偿漏波结构中的正色散；（2）利用non-Foster电路等方法研究新型非色散漏波结构；（3）探讨负色散、负群速、non-Foster等超光速电磁特异传播结构的工作机理；（4）最终优化设计宽带高增益波束不随频率变化的漏波天线（预实验结果）。其成果可应用于无线通信系统，对解决行波天线和天线阵的波束随频率偏斜问题、电路系统中的色散失真问题有很大的应用价值；此外，对宽带特异材料的创新研究，对超光速电磁特异结构的电磁理论研究有重要的学术意义。

漏波天线具有成本低、馈电容易、阻抗带宽大、波束窄和增益高的优点，但是漏波天线主波束方向往往会随频率而发生变化，导致其应用范围受限。本项目围绕如何解决漏波天线主波束随频率变化的问题展开研究，已取得的重要结果有：（1）提出了一个紧凑型的相位补偿漏波天线结构，实现了漏波天线较大带宽内主波束方向固定，该主波束可设计在任意方向；（2）提出了一种基片集成行波天线，分析了其表面波和漏波传播特性，实现了在较大带宽内主波束在端射方向附近固定，该天线具有平面结构、带宽大和高增益优点。此外，本项目还针对周期性漏波天线由于其边射阻带导致主波束扫描受限问题，提出了系列方法抑制边射阻带，实现了漏波天线宽角度连续扫描；针对平面谐振类天线带宽窄的问题，提出了边射辐射的宽带SIW天线、全向辐射的宽带平面天线等天线。以第一/通信作者发表重要论文15篇，包括在IEEE发表的SCI收录期刊论文14篇，在天线与微波领域顶级国际期刊（IEEE Transactions on Antennas and Propagation和IEEE Transactions on Microwave Theory and Techniques）发表论文9篇。这些研究对发展漏波天线、表面波天线、SIW天线和微带天线有重要的学术意义和应用价值。