Research And Design On Broadband And High Efficiency RF Power Amplifiers

Extending the bandwidth and improving efficiency are all the way two important directions of power amplifiers research.But traditional harmonic tuned power amplifiers generally depend on precise manipulation of harmonics in addition to the fundamental frequency,which increases complexity of matching network design and confines bandwidth.Therefore,it is a difficult task for the conventional harmonic tuned power amplifiers to meet the broadband and high efficiency requirement,simultaneously.To this end,a new type of harmonic control power amplifier design concept,namely class-J power amplifier,is proposed.The design of proposed class-J power amplifier is to comprehensively consider the performance of bandwidth,efficiency and output power.It can improve the bandwidth while preserving high efficiency of power amplifiers,and greatly solve the contradiction between bandwidth and efficiency.This work focuses on the design of broadband and high efficiency RF power amplifiers,focusing on the deign method of class-J power amplifier.The specific contents and innovation points are given below.1.The basic theory of class-J power amplifiers is systematically introduced and summarized.Firstly,the derivation conditions and process of class-J power amplifier are given.Next,using the drain output voltage and current waveform to illustrate the harmonic controlled principle of class-J power amplifier.Finally,employing the most important continuous mode of operation and the concept of design space to give the reason why the class-J amplifier has broadband characteristics.2.With a specific output network structure,the design principle of a traditional class-J power amplifier is introduced.And shortcomings of conventional design method are pointed out by simulation and tests.Then,another traditional design method of broadband and high-efficiency power amplifiers,namely real frequency technology,is analyzed.At the same time,the existing problems are given and a new network synthesis method of the class-J power amplifier is proposed.This method not only realizes class-J power amplifier with simultaneous control of the fundamental and harmonic impedances,but also the specific parameters of matching networks can be synthesized,which can further enhance the broadband and high efficiency performance of the class-J power amplifier.Finally,comprehensive equations and complete design procedures of the method are given.3.The traditional method and new network synthesization method are both used to design and implement a class-J power amplifier.The experimental test proves the potential of class-J power amplifier with broadband.Compared with the traditional method,the new method can achieve better bandwidth and efficiency performance of class-J power amplifier.And this method is more versatile and flexible.