以平行化有限差分時域法分析八木宇田類型奈米天線

Abstract

時域有限差分法已被廣泛運用在諸多模擬光電電磁計算上，我們以C++語言，自行開發時域有限差分模擬器，並且具有平行化功能，透過訊息傳遞介面協定，利用多台電腦平行處理加速運算，以減少運算時間。 本論文主要分析並探討金屬跟非金屬結構的奈米天線的遠場性質及其表現 差異，並專注在八木宇田天線的相關結構上。非金屬因為損耗性遠比金屬低，逐漸地受到了注目；八木宇田天線以強大的指向性為特點，但傳統八木宇田天線卻有著體積過大的缺陷導致應用受限。而奈米結構本身體積足夠小，可充分克服傳統八木宇田的問題。我們主要用寬頻點波源來取代平常用的平面波來凸顯其方向性的特點。我們分析球狀奈米天線，並比較金屬跟非金屬的差異，且將金屬結構置於基板上以增加實用性。之後還探討圓柱棍狀的八木宇田奈米天線，可以看到更進一步的方向性增強。

The finite-difference time-domain method (FDTD) has been widely used in computational electromagnetics. We developed a parallelized three-dimensional (3-D) FDTD simulator in C++ language. The message passing interface (MPI) protocol is applied to our simulator for parallelizing several computers in the computation in order to speed up the process and shorten the simulation time. In this research, the main topic is to analyze the far-field properties of metallic and all-dielectric nano-antennas, and we focus on Yagi-Uda type structures. Due to low loss, the all-dielectric nano-antennas have earned much attention recently. Yagi-Uda antennas possess high directivity, however the large size of their structure is a major drawback. Yagi-Uda nano-antennas have relatively small size, thus it can avoid the size drawback. In this research, the wave source is a broadband single emitter. We analyze nano-antennas and discuss the difference between all-dielectric and metallic structures. Considering practical applications, we also study the Yagi-Uda nano-antennas on substrate. On the other hand, the Cylindrical-Rod Yagi-Uda nano-antennas are also investigated in this thesis.