用超材料表面結構設計微型化米凱利安透鏡

Abstract

近期以來，超材料表面結構(metasurfaces)的研究已越來越普遍，由於此種結構可以產生任意數值的介電係數與導磁係數，因此可以用來製造表面波透鏡並且應用於各式各樣的工程中，例如奈米聚焦、傳導、偵測和光譜成像。本篇論文我們使用正方型金屬片搭配介電質的接地週期結構來合成較一般圓形表面波透鏡更微小的正方型米凱利安透鏡。我們使用CST模擬軟體來展示此擁有良好聚焦效應透鏡的設計結果，我們也定義出了能量集中度和穿透效率來量化我們設計的透鏡。最重要的是，本論文成功地提出了週期性結構與米凱利安透鏡之間的連繫，並且成功地應用矩形外型節省了透鏡尺寸。

Research on metasurfaces has been widespread recently because it can generate arbitrary permittivity and permeability which can be used to synthesize different types of flat surface-wave based lens for engineering applications such as nanofocusing, sensing, detection, and spectral imaging. In this paper, we use the periodic array of square metallic patches etched over a thin grounded dielectric sheet to synthesize a flat Mikaelian lens of rectangular shape that is smaller than contemporary circularly-shaped lens. The design is validated by CST simulation results, which demonstrate the effectiveness of the focusing. The power concentration and transmission efficiency have been defined to quantify the lens performance. In addition, the linkage between the periodic structure and the Mikaelian lens has been proposed successfully in this thesis. Most importantly, we successfully use the rectangular shape to reduce the size of lens.