波导式人工电磁媒质及其在微带天线中的应用研究

The development of modern wireless communication is demanding for antennas with advanced performances such as broad bandwidth, multi-band operation and weak mutual couplings. Besides, miniaturization and easy fabrication and integration are also required for modern antennas. Waveguided metamaterials,which is proposed recently by the applicant and his collaborators, can achieve various electromagnetic- wave-controlling capabilities, which can be utilized to improve antenna performance of different kinds. Waveguided metamaterials are constructed in planar waveguide environment by etching planar periodical patterns in the lower metal plate. Hence they can be fabricated with normal PCB art and is easy to be integrated with planar circuit and antennas. In this project, effective medium properties of waveguided metamaterials are studied and novel waveguided metamaterials with high performance including waveguided magneto-dielectric materials, waveguided single-negative metamaterials and waveguided metamaterials with band-stop characteristic are developed. Moreover, we will design novel compact and easy-fabricate antennas with improved performance including broadband microstrip antennas loaded with waveguided magneto-dielectric materials, dual-band and high-broadside-directivity microstrip antennas loaded with the combination of waveguided single-negative metamaterials and waveguided magneto-dielectric materials, and microstrip antenna arrays with weak mutual coupling based on waveguided metamaterials with band stop characteristic. New technical approaches to realizing modern antennas with high performance will be developed through this project.

现代无线通信技术的发展要求天线在具有较高电性能同时还要具备小型化、易加工、易于和电路集成等特征。近年由申请人和他人合作提出的波导式人工电磁媒质能够实现丰富多样的电磁波控制功能，可用于改善天线多方面的电性能，此外，它通过在平板波导下金属板上刻蚀平面周期结构来实现，适合用印刷电路板工艺加工，便于和平面电路及天线集成。本项目将对波导式人工电磁媒质的等效媒质性质进行研究，进而开发高性能的波导式人工磁电介质、波导式人工单负媒质以及带阻性波导式人工电磁媒质，并利用它们研制结构紧凑、易于加工的新型高性能天线，包括基于波导式人工磁电介质的宽带微带天线、基于波导式人工单负媒质和波导式人工磁电介质组合体的高边射定向性双频带微带天线以及基于带阻性波导式人工媒质的弱互耦微带天线阵列，为现代高性能天线的实现探索新技术途径。

无线通信技术的发展对终端天线提出诸如宽频带工作、多频段工作、弱互耦等高性能要求，本项目目标在于利用波导式人工电磁媒质丰富的电磁波调控特性研发新型高性能微带天线。本项目首先设计出基于嵌入式弯曲线结构的二维各向同性波导式人工磁电介质、基于嵌入式弯曲线结构和互补开口谐振环结构的波导式双正-近零分层式组合人工媒质，以及基于交叉弯曲线缝隙结构的具有谐振带阻特性的波导式负磁导率人工媒质。然后利用这些波导式人工媒质设计新型高性能微带天线：1）将波导式人工磁电介质用作圆极化微带贴片天线的等效基底，所得新型圆极化天线的阻抗和轴比带宽比传统同尺寸圆极化贴片分别拓宽了125%和133%；2）将波导式双正-近零分层式组合人工媒质作为等效分段基底，实现出工作于LTE和WiMAX频段的具有一致边射式辐射特性的双频带微带天线；3）将带阻性波导式负磁导率人工媒质置于紧密相邻的微带贴片天线之间，获得具有显著弱互耦特性的二元、三元以及四元微带贴片天线阵列。由于波导式人工电磁媒质通过在平板波导的下金属板上刻蚀平面周期结构来实现，适合用印刷电路板工艺加工，所以本项目所设计的天线同时具备结构紧凑、易于加工和电路集成等优点。本项目的研究成果为现代无线通信用高性能天线的实现提供了可能的技术途径和有益的参考。