隨著第五代行動通訊與物聯網時代的來臨，無線通訊裝置的需求日益增加，在無線通訊系統中，射頻功率放大器是其中關鍵的元件之一，因為它在射頻收發機中占了超過一般的功率效耗。而功率放大器之效率藉由功率有效轉換率與直流功耗多寡，可以推得裝置使用之時間；此外功率放大器之輸出功率也決定了功率訊號傳遞的距離。
為了在效率與輸出功率間尋求解決方法，本篇論文提出一個操作於3.5GHz之Doherty功率放大器模組，可以應用於第五代行動通訊之基地台，此功率放大器模組之主要特色具有高效率與高輸出功率且在一定程度之輸出功率回退上也保持良好的輸出效率。
本論文將對設計功率放大器之性能指標做探討再進一步研究Doherty功率放大器之架構和設計方法，另外搭配設計威金森功率分配器以及產生90度相位差之四分之一波長傳輸線。
最後實現操作於3.5GHz之Doherty功率放大器之模組，在輸入功率為25dBm時具有50dBm之輸出功率、功率增益為25dB，功率附加效率達到52%。此外在輸出功率回退6dBm時，功率附加效率達47%。

With the coming of the fifth generation communication systems and the IOT era, the demand for wireless communication device is growing day by day. When it comes to wireless communication systems, RF power amplifiers are playing a significant role because they take more than a half power consumption in RF transceivers. The efficiency of a power amplifier is defined by the power conversion rate and power consumption, which directly affects the time consuming of the device. Besides, the output power of the power amplifier also determines the transmission distance of the signal. Unfortunately, the efficiency of the power amplifier is incompatible with its output power.
In order to reach a trade-off between efficiency and output power, this thesis proposes a Doherty power amplifier module operating at 3.5GHz, which can be applied to the base station of the fifth generation communication systems. The main feature of this power amplifier module is that it could reach high output power and high efficiency, even at the power back-off condition. In this thesis we will discuss indices of performance about the power amplifier design, and more details about structure and design of Doherty power amplifier module, while cooperating with the design of Wilkinson power divider and ninety degrees Quarter-wavelength transmission line.
We successfully designed a Doherty power amplifier module operating at 3.5GHz, reaching a result with 25 dBm and 50 dBm for Pin and Pout, respectively, and the power gain is 25 dB, while the PAE is 52%. In addition, when the power back-off is 6dBm, the PAE can still reach 47%.
Keyword: High efficiency、Doherty、OPBO、Wilkinson power divider、5G、Base station

口試委員會審定書 #
摘 要 i
ABSRACT ii
目錄 iv
圖目錄 vii
表目錄 xi
第1章 緒論 1
1.1 研究背景以及動機 1
1.1.1 研究背景 1
1.1.2 研究動機 2
1.1.3 第五代行動通訊系統(5th Generation Communication) 3
1.1.4 基地台(Base-Station)之分類與市售產品比較 4
1.2 章節概論 6
第2章 功率放大器 7
2.1 功率放大器的分類 7
2.1.1 線性功率放大器 8
2.1.2 線性功率放大器之比較 15
2.2 功率放大器設計之小訊號考量 17
2.2.1 S-參數(S-parameter) 17
2.2.2 反射係數(Reflection coefficient) 19
2.2.3 功率以及功率增益(Power and Power Gain) 21
2.2.4 穩定度(Stability) 25
2.3 功率放大器設計之大訊號考量 29
2.3.1 線性度與P1dB、動態範圍以及三階交互調變失真 29
2.3.2 效率(Efficiency) 35
2.3.3 功率回退(Back-off) 36
2.3.4 鄰近通道功率比(Adjacent channel power raito, ACPR) 37
2.4 負載線理論(Load Line Theory)與負載牽引(Load Pull) 38
第3章 Doherty功率放大器 43
3.1 Doherty功率放大器架構以及原理 43
3.1.1 Doherty之基本架構 44
3.1.2 Doherty功率放大器之操作模式 46
3.2 威金森功率分配器(Wilkinson Power Divider) 50
3.2.1 威金森功率分配器之分析及特性 51
3.2.2 威金森功率分配器之模擬 51
第4章 設計Doherty功率放大器模組與量測 53
4.1 Doherty功率放大器模組設計以及模擬 53
4.1.1 Doherty功率放大器模組設計流程 54
4.1.2 Doherty功率放大器模組之設計規格 55
4.2 單級功率放大器之設計 56
4.2.1 決定單級功率放大器之偏壓以及直流消耗功率 56
4.2.2 穩定度(Stability)模擬 57
4.2.3 負載牽引(Load Pull)模擬 60
4.2.4 實現單級功率放大器 61
4.3 Doherty功率放大器含威金森功率分配器之設計 65
4.3.1 威金森功率分配器(Wilkinson Power Divider)之設計 66
4.3.2 威金森功率分配器含產生90度相位差之傳輸線 69
4.3.3 Doherty功率放大器與Class AB類Combine電路 72
4.4 驅動級功率放大器之選取 76
4.4.1 決定所需輸出功率與驅動放大器的選取 76
4.4.2 決定驅動功率放大器所需偏壓和直流功率消耗 77
4.4.3 穩定度(Stability)模擬 78
4.4.4 負載牽引(Load Pull)模擬 79
4.4.5 實現驅動級功率放大器 81
4.5 實現Doherty功率放大器模組 85
4.5.1 包裝(Package)Doherty功率放大器模組 85
4.5.2 量測Doherty功率放大器模組 86
第5章 結論 93
參考文獻 95

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