本論文之研究主題為圓極化摺疊反射陣列，而在近年為了解決5G網路覆蓋度不足的問題，已計畫使用衛星通訊解決此問題，因此吾人將頻率設計於5G網路內37 GHz，然而在舊有的圓極化摺疊反射陣列設計中，雖然有效能好的研究，但是該架構難以於37 GHz實現，因此吾人將改變其架構，以適用於Ka波段圓極化摺疊反射陣列，吾人之Ka波段圓極化摺疊反射陣列主要分為兩個部分，圓極化選擇表面與圓極化反射陣列。
吾人之圓極化選擇表面使用吾人所設計的三層介質架構，以解決舊有的圓極化選擇表面架構難以於高頻製造之缺點，也降低架設圓極化選擇表面時的誤差，並在此架構基礎下設計非對稱十字單元，使得圓極化選擇表面反射損失降低。
而圓極化反射陣列則使用吾人所設計之扇形十字單元，扇形十字單元只使用一層介質，可降低成本以及架構複雜度，並增加一共振環以增加此單元相位可變化之範圍，此款扇形十字單元可變相位範圍大約為500°，並且此架構的反射損失在不同相位時皆可維持於0.5 dB內。
將圓極化選擇表面與圓極化反射陣列組合為圓極化摺疊反射陣列後，經過量測我們得到此架構之效能為，最高增益26.8 dB和30.6 %的孔徑效率與9.45 %的3-dB增益頻寬，與3-dB軸比頻寬12.2 %。

The topic of this thesis is the circularly polarized folded reflectarray. In recent years, in order to solve the problem of insufficient 5G network coverage, it has been planned to use satellite communication to solve this problem. Therefore, we designed the frequency at 37 GHz in the 5G network. However, in the old circularly polarized folded reflectarray design, although the effective performance is good, the structure is difficult to achieve at 37 GHz, so we will change its structure to be suitable for Ka-band circularly polarized folded reflect arrays. The Ka-band circularly polarized folded reflectarray is mainly divided into two parts, the circularly polarized selective surface and the circularly polarized reflectarray.
Our circular polarization selective surface uses the three-layer dielectric structure designed by us to solve the disadvantage that the old circular polarization selective surface structure is difficult to manufacture at high frequencies, and also reduces the error when erecting the circular polarized selective surface. The asymmetric cross element is designed on the basis of this architecture, so that the reflection loss of the circular polarization selective surface is reduced.
The circularly polarized reflectarray uses the fan-shaped cross unit designed by us. The fan-shaped cross unit only uses one layer of dielectric, which can reduce the cost and the complexity of the structure, and add a resonant ring to increase the range of the phase change of the unit. The variable phase range of the cross unit is about 500°, and the reflection loss of this structure can be maintained within 0.5 dB at different phases.
After combining the circularly polarized selective surface and the circularly polarized reflectarray into a circularly polarized folded reflectarray, we obtained the performance of this structure by measuring the maximum gain of 26.8 dB, the aperture efficiency of 30.6 % and the 9.45 % 3-dB Gain bandwidth, 12.2 % bandwidth over the 3-dB axis ratio.

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