提出了一种新型二维左手材料结构单元,该结构由介质板及其两侧放置的两个反向对称的Z形金属条组成.在电磁波垂直于介质板和平行于介质板入射两种情况下,这种结构单元于X波段均表现出左手通带特性.通过模拟仿真,提取等效电磁参数,建立等效磁谐振电路模型,分析验证了该结构的左手特性.并将双Z形结构与相似的工字形结构相比较,发现在电磁波垂直入射时两种结构均出现相似的左手通带,而在电磁波平行入射时,只有双Z形结构实现了双负特性.结果表明这种双Z形左手单元结构具有更优越的电磁波入射适应特性,即实现了双入射型左手结构单元.
A new 2D left-handed material structural unit is proposed by setting two reversely symmetrical Z metal strips on each side of the dielectric substrate respectively. The structure can present left-handed properties in X waveband,with electromagnetic waves incident either perpendicularly or parallel to the plane of the substrate. By means of numerical simulation,extracting the effective permittivity and permeability from S parameters and building the equivalent magnetic resonance circuits of the structure,the left-handed property is further analyzed and verified. And by comparing the double Z-shape unit with the traditional H-shape unit,it is shown that they have similar responses of presenting left-handed pass band when electromagnetic waves are incident perpendicularly to the substrate,but only the double Z-shape unit can achieve left-handed features when electromagnetic waves are incident parallel to the substrate. The results indicate that the double Z-shape left-handed structural unit is superior to the traditional H-shape structure,namely,the double Z-shape can redound to design left-handed structural unit for double dimension incidence of electromagnetic waves.