摘 要 隨著無線通訊技術的進步再加上大量資訊傳送的要求下，寬頻無線區域網路逐漸的受到重視。而系統中的高頻微波電路是位於收發端(RF section)，其中功率放大器控制了射頻收發模組大部份的尺寸、成本與效能，因此功率放大器在此系統中扮演最重要角色。 本論文主要在設計高效率與線性度的整合性單石微波積體電路(monolithic microwave integrated circuit ; MMIC)之功率放大器(power amplifier)。其中高效率之功率放大器乃利用E類偏壓方式及GCS公司的InGaP/GaAs HBT技術，設計出1.8 GHz E類兩級功率放大器。而在線性度改善的功率放大器設計則採用主動元件(GCT公司的InGaP/GaAs異質接面雙極性電晶體)的基射極接面之二極體配合並聯電容組成主動偏壓電路，來取代傳統電阻式偏壓方式。此主動偏壓電路可以在不犧牲額外的功率損耗下，得到線性度改善的5.2 GHz兩級功率放大器。電路設計是使用Agilent ADS軟體，而電路測量則利用HP-8510C網路分析儀及Maury ATS負載–拉移(load-pull)量測系統，將所有微波積體化功率放大器作完整的S參數、功率增益、輸出功率、附加功率效益(PAE)、三階交互調變失真及鄰近通道干擾功率比值量測，並對結果探討分析。 1.8 GHz E類兩級功率放大器之測量結果為：(1)小訊號為S11 = -11.4 dB，S21 = 24.2 dB，S22 = -5.52 dB；(2)功率增益為24.2 dB，最大輸出功率為15.5 dBm，最大附加功率效益為39.4 %，OIP3為22 dBm，NADC系統的鄰近通道干擾功率比為-30 dBc。 主動偏壓電路之5.2 GHz兩級功率放大器的量測結果與相同偏壓狀態的電阻式A類功率放大器比較，結果增益壓縮改善了2dBm的輸入，OIP3增加了0.8dBm。 With the current expansion of the wireless communication industry,system integration has become a major trend to meet hallenges.Microwave circuits are used within RF section of wireless communication system.The power amplifier is controlled by the size,cost,and performance of the RF section,hence the power amplifier plays an important role in the wireless communication system. This thesis is major to design high efficiency and linearization MMIC (monolithic microwave integrated circuit)power amplifier.In the high efficiency MMIC power amplifier,the paper demonstrated the 1.8GHz class E power amplifier.In addition,it is shown to use active elements (InGaP/GaAs HBT)’s base-collect junction and combine a parallel capacitance to form active bias.Active bias replace resistance bias without power consumption.This design is 5.2GHz two stage power amplifier to improve the nonlinear factor of power amplifier—gain compression.Then using network analyzer (HP-8510C) and Maury ATN load-pull system to measure all microwave power amplifiers.The measurements include S parameter, power gain,output power,PAE,IM3,and ACPR and analyze the results further. The measured result of 1.8 GHz power amplifier is as followed:(1) small signal S11 = -11.4 dB，S21 = 24.2 dB，S22 = -5.52 dB.(2) power gain= 24.2 dB,maximum output power=15.5 dBm,maximum PAE=39.4%,OIP3=22 dBm,ACPR=-30 dBc The measured result of 5.2 GHz active bias power amplifier is compared to the resistance bias class A power amplifier.The result is improvement of gain compression of 2 dBm input and improvement of OIP3 of 0.8 dBm.
