基于non-Foster元件的宽带电小天线及超方向性阵列关键问题研究

With the development of wireless communication systems toward miniaturization and compact configuration, the improvement of electrically small antenna and array technologies is in urgent requirement. However, limited by the classical antenna theory "Chu limit", the realization of electrically small antenna and array with broadband, high efficiency, and high-directivity radiation at the same time, has become a historical problem in the industry. This project aims to study the basic theories, effective approaches, and key technologies to realize the high-performance electrically small antennas and super-directivity arrays, by means of the non-Foster (NF) technology which is popular in recent years. First of all, with the aid of the unique NF circuit reactance advantage, the low Q electrically small antenna theories and technologies are explored; At the same time, the near-field coupling mechanism of high-density electrically small array is investgdated, and semi-analytical coupling model is builded accordingly; Secondly, the NF circuits are incorporated into the high-density electrically small array design gradually and the system level studies are carried out, so as to accomplish the electrically small array deisgn with both broadband and super-directivity radiation; Thirdly, the tradeoff between the NF antenna/array radiation performance and system stability is evaluated; Finally, the design optimization scheme for the NF electrically small antenna system is improved by organically compounding the above research results, and the academical experimental verification is accoplished. This project research will provide a complete and efficient design idea, a strong theory support, as well as a scheme architecture, for the active electrically small antenna and array designs with the performances beyond the Chu limit.

随着无线通信系统向着小型化、紧凑化方向发展，迫切要求发展电小天线及阵列技术。然而，受限于经典天线理论Chu极限，同时实现电小天线及阵列的宽带化、高效率、以及高方向性，已成为业界亟待解决的历史性难题。本项目旨在以近年来流行的非福斯特（non-Foster，NF）技术为手段，系统深入地研究实现高性能电小天线及超方向性阵列的基础理论、有效途径与关键技术。首先，借助于NF电路独特电抗优势，探索低Q电小天线设计理论与技术；同时，研究紧凑电小阵列近场耦合机制，并建立半解析耦合模型；进而，将NF电路逐步融入紧凑阵列中进行系统级研究，以实现兼顾低Q与超方向性优势的电小阵列设计；然后，评估NF天线系统辐射性能与稳定性间的制约关系；最终，有机集成上述成果，完善NF电小天线系统最优化设计方案并完成原理性实验验证。项目研究将为突破Chu极限的有源电小天线及阵列设计提供完整而高效的设计思路、理论支撑及方案体系。

随着无线通信系统朝着小型化、紧凑化方向发展，天线单元的小型化、集成化以及阵列的紧凑化已成为目前无线通信射频前端系统中天线子系统发展的重要课题。其中，物理尺寸远小于空间工作波长特征的电小天线及阵列无疑是该课题研究的主流之一。然而，具有深度小型化和高度集成化优势的电小天线及阵列，受限于Chu limit 理论，如何实现电小天线及阵列的宽带化、高效率、以及高方向性，已成为业界亟待解决的历史性系列难题。为了攻克以上系列难题，本项目进一步发展了无源电小天线理论与技术，并研究了对天线及阵列与有源电路进行整合系统级分析与设计。通过逐步将非福斯特（non-Foster）电路有效地融入天线设计之中，设计出完全突破 Chu limit 的宽带高增益non-Foster 电小天线，并进行了全面地稳定性分析。本项目研究为电小天线及阵列的宽带化、高效率、以及高方向性设计提供了着实有效的技术支撑。.详细地，本项目首先基于电小天线最基本的辐射机理，探索了近场谐振寄生耦合结构的电小天线表面电流分布与电磁场的近、远场分布的实质性联系，从而在最大程度上实现电小尺寸、低剖面的同时获得更宽的带宽，并最终发展了一系列高性能的电小天线；然后，通过对高密度阵列进行研究，深入挖掘了高定向性天线及阵列极其复杂的近场分布，探索了谐振器在距离非常近的条件下的强场耦合物理机制，从而建立起阵元间耦合模型，并通过利用近场谐振寄生技术发展了系列惠更斯源电小天线，为该类高定向辐射电小天线提供了一套系统的设计准则。再则，借助non-Foster 电路独特电抗优势，将non-Foster电路逐步融入电小天线中进行系统级研究，以实现兼顾低Q与高增益优势的电小天线，并依此发展了non-Foster有源加载的天线/滤波器，并进一步评估了non-Foster天线系统辐射性能与稳定性间的制约关系。本项目研究成果为突破 Chu limit的有源电小天线及阵列设计提供了高效的指导方法与设计方案。