用超材料設計米凱利安透鏡

Abstract

近來，超材料表面結構(metasurfaces)的研究已經相當多元且廣泛，如在無線通信、天線設計以及微波組件中都有其應用，因為超材料表面結構有著特殊的電磁和色散特性，可以利用於控制表面波的反射特性和制定表面等離子激元（SPPs）的傳播行為。本文中，提出了窄型的矩形米凱利安透鏡，它利用正方形金屬貼片的週期性排列並蝕刻在薄的接地介電質基板上來合成透鏡。對於這漸變指數（GRIN）透鏡，我們考量到電磁平面波的行徑方向對合成折射率的影響，提出了更新穎的透鏡結構的設計方式，並經由CST模擬軟體驗證。針對模擬結果，定義兩種不同的量化分析方式，分別為垂直聚焦比率和橫向集中定焦，以此用來分析能量的分佈，展示出米凱利安透鏡具有更佳的聚焦效果。

Research on metasurface has been quite diverse and extensive, such as in wireless communications, antenna design and microwave components. Because metasurface has special electromagnetic and dispersion characteristics, it can be used to control the reflection properties and to develop the propagation behavior of surface plasmon polaritions (SPPs). In this paper, we propose a thin rectangular Mikaelian lens. It is periodically arranged by a square metal patch and etched on a thin ground dielectric substrate. For this graded index (GRIN) lens, we consider the effect of the direction of the electromagnetic surface wave on the refractive index. A more innovative design method is proposed and simulated by CST simulation software. Two different quantitative analysis methods are defined for the simulation results, which are respectively the vertical fixed focus and the horizontal focus width. The distribution of power is analyzed in detail. It is proven that the Mikaelian lens can have a better focusing effect.