| Wireless mobile communication system evolves toward multiple operating modes and high rates constantly.The power amplifier is an important component of the RF front end in the communication system,and its broadband performance and high efficiency performance are the basis for achieving high-speed communication and green operation.Class-J power amplifier is a new type of power amplifier that has that has been brought on the carpet in recent years in recent years.It brings new ideas to power amplifiers design with its harmonic control theory and continuous working mode concept.Studying the researches carried on class-J power amplifiers,three background points are included:?1?Most researches of class-J power amplifier focuse on improving the efficiency via improving the matching network structure.On the other hand,the relationship of high efficiency with waveform of class-J power amplifier are not deeply studied;?2?The continuous working mode is used to improve the amplifier's bandwidth,but the improvement is limited;?3?The application researches of the class-J power amplifier in the 5G system are not enough.The work of this thesis is foucs on these background and aim at a deep study about class-J power amplifier and its application design in the 5G system.First of all,the harmonic control theory of class-J power amplifier is studied and the influencing factors of high-efficiency waveforms of power amplifier are explored in the thesis.Secondly,the transformed impedance space is studied to improve the average efficiency of power amplifiers by adding external expansion capacitors based on the continuous space theory.Thirdly,focusing on the theory of Class-J power amplifier and its application in 5G systems,a dynamic match network of high efficiency Class-J power amplifier is studied to solve the problem of lower average efficiency of power amplifier beacause of the high peak average ratio signal in 5G communication system,and the design and physical verification of high-efficiency class-J power amplifier based on dynamic match network has been completed.The specific workes of the thesis are as followed:1.Summarize the main technical indicators and basic work concepts of Class-J amplifiers systematically.The harmonic control theory of Class-J power amplifier combined with the waveform theory is analyzed,and the reason of high efficiency output of Class-J power amplifier is explained in the perspective of waveform control.Analyzing Class-J power amplifier's continuous working mode,and the reason of good bandwidth characteristics in Class-J power amplifier is clarified.2.Analyze and study the influencing factors of high-efficiency waveforms in Class-J power amplifiers,and conducting waveform comparison research from three aspects: device selection?input power value and matching network differences.Focus on studying the voltage and current peak value of the drain output waveform and the proportion of DC components,analyzing the reasons of limiting the efficiency of the Class-J power amplifier.A broadband high-efficiency Class-J amplifier working at 3.34.2GHz is designed based on the results of the waveform analysis,.3.Analyze and study the impedance space of Class-J amplifier.The output capacitance Cout of the class-J amplifier is analyzed,and the feasibility of using the output capacitance to construct a dynamic impedance space is studied.The relationship between the optimal impedance and efficiency is analyzed.Using tunable devices to build a dynamic impedance match network to expand its impedance match area of Class-J amplifiers to improve efficiency.4.Based on the waveform analysis results and the dynamic match network research work,the class-J power amplifier with dynamic match network is designed and completed for the application of 5G system.Class-J amplifier achieves 43.1%50.6%power-added efficiency,the maximum output power is 39.8dBm,the maximum power-added efficiency 44.7%at 4dB output power back-off.The works conducted in this thesis has reference value for the theoretical research and engineering application of class-J power amplifier. |
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