Improved patch antenna performance by using a metamaterial cover

INTRODUCTION Metamaterials are periodic metallic structures exhibiting unique properties not existing in natural materials. They are also called backward wave mate- rials, double negative materials, or left-handed mate- rials (LHM) in particular, in which the vectors E, H and k form a left-handed system. Since the idea pro- posed by Veselago (1968), metamaterials have at- tracted great interest in the last years (Smith et al., 2000; Pendry, 2000; Smith and Kroll, 2000; Shelby et al., …     

复数的方位概念与方位关系式及其在复集中的应用

从复数的方位概念与方位关系式的引入开始，阐明了复数间的关系。指出了复数可类似实数那样研究各种“不等关系”——即“方位关系”，从而丰富了复数构造论．最后给出了它在复集理论中的应用。     

小型化20dB宽带定向耦合器设计

本文运用PCB带状线覆盖介质使奇模相速下降,而偶模相速近似不变等特点设计并制作宽带耦合器。它具有体积小、重量轻、损耗低且具有方向性、指标好等特点,可应用于POI(多系统合路平台)、DAS(分布式天线系统)及微波测量系统等,带宽从727MHz到2170MHz,适用面广。