利用具有正或負折射率的分裂式環形共振器超材料合成微波聚焦透鏡

Abstract

近年來，超材料已經被廣泛地研究在文獻和實驗中，由於它們能夠產生特別的介電常數和導磁率可被用來改善現有裝置的特性。超材料的結構設計在於它能夠同時有負的介電常數和導磁率，這也被稱為左手材（LHM）。左手材料能夠產生出負的折射率，並且生成後向波，甚至能夠增強電磁場。除此之外，左手材料可以用於設計透鏡並且達到比傳統透鏡更好的聚焦效果。 在這篇論文中，我們使用分裂式環形共振器和金屬線當作單元材料並且合成多種透鏡。具體來說，我們合成正折射率透鏡也就是傳統式透鏡，還有負折射率透鏡和拋物面折射透鏡來實現聚焦效果。論文中我們使用CST模擬軟體來模擬證實聚焦系統的效能。最後，我們也分析並比較不同種類透鏡的聚焦效果。

Metamaterials had been widely investigated in literature and experiment in recent years, because of they are able to produce unusual permittivity and permeability which can be used to improve the performance of conventional devices. Metamaterial structures designed to have simultaneously negative permittivity and permeability are known as left-handed materials (LHM). LHM can exude negative refractive indices, generate backward-waves, and even enhance the electromagnetic fields. LHM can be employed to design transformed lenses with better focusing efficiency than conventional one. In this thesis, we make use of the square split-ring resonator and wire as the unit cell to synthesize a number of lenses. Particularly, we synthesize a positive refraction index lens which is conventional lens and a negative refraction index lens and a parabolic refraction lens to achieve focusing effect. CST has been employed to demonstrate the performance of the focusing system. Finally, we analyze the focusing effect of different lens.