本論文旨在設計一種應用於太陽能無線電力傳輸系統中的環狀波導結構，以降低光束在自由空間中的擴散角，並提升傳輸效率。以圓柱座標下的有限時域差分法進行模擬分析。本研究針對不同的參數條件進行優化與性能比較，以找出最佳化的波導設計。模擬中比較了四方晶格與Bessel分布兩種不同的結構排列方式。結果顯示，在最佳參數條件下，四方晶格排列波導的傳輸效率為11.85%，其在E_φ與E_r平面中的半擴散角分別為1.70°與1.46°；而Bessel排列波導的最佳傳輸效率則為22.76%，其半擴散角分別為2.06°與1.19°。進一步在9.7 GHz頻率下，估算其結構體積，四方晶格排列約為0.44m^3，Bessel排列為1.41m^3，展現出高效能與小型化兼具的設計潛力。研究結果指出，透過適當設計的環狀波導結構，可有效抑制光束發散，並提升能量傳輸效率。該結構提供一種不同於傳統矩陣式或碟型天線的新型解決方案，具有潛力應用於未來的無線電力傳輸系統中。;This paper aims to design a torus photonic crystal waveguide structure for application in space-based solar wireless power transmission systems, with the goal of reducing beam divergence in free space and enhancing transmission efficiency. The simulation and analysis are conducted using a finite-difference time-domain method in cylindrical coordinates. In this study, different parameter settings are tested and compared to find the best-performing waveguide design. Two types of structural arrangements are examined: square-lattice and Bessel structure. The results show that the square-lattice waveguide reaches a transmission efficiency of 11.85%, with half divergence angles of 1.70° and 1.46° in the E_φ and E_r planes. The Bessel structure waveguide achieves a higher efficiency of 22.76%, with half divergence angles of 2.06° and 1.19°. Under the operating frequency of 9.7 GHz, the corresponding structural volumes of the square-lattice and Bessel configurations are estimated to be approximately 0.44m^3 and 1.41m^3. These results demonstrate the feasibility of achieving compact volume and high performance simultaneously. The results indicate that a well-designed torus waveguide can effectively reduce beam spreading and increase energy transmission efficiency. This design offers a new solution, different from traditional array or parabolic antenna systems, and shows promise for future wireless power transmission applications.
