Research And Design Of Broadband High Back-off Doherty Power Amplifier

Power amplifier(PA)occupies an important position in wireless communication systems.In terms of PA theory,switching mode PAs have the following shortcomings:(1)the design process of Class E PAs ignores the strict requirements for output waveforms;waveform analysis techniques are not applied to the design of Class E PAs;(2)the concept of“continuous PA mode”cannot be directly applied to the design of bandwidth expansion of Class E PAs.In terms of PA application,although Doherty PA(Doherty PA,DPA)is widely used in 5G communication systems,it also faces great challenges:(1)DPA operating bandwidth problem;(2)DPA high back-off range problem.This thesis addresses the above issues by firstly,studying and proposing a new harmonic-tuned(HT)class E PA theory;secondly,proposing a generalized factorial factor theory for bandwidth extension of the new HT class E PA;finally,applying the above work to the DPA design to improve the DPA's back-off efficiency,back-off range and bandwidth.The specific works of the paper are as follows:1.Theoretical research on the new HT class E PA.The difficulty of applying waveform analysis technology in traditional class E PA design is analyzed,and a new waveform theory aiming at obtaining the harmonic output impedance in the form of pure reactance is proposed.The output waveform obtained is closer to the ideal class E PA output waveform.This work can facilitate the HT design of class E PAs.As a verification,the paper uses CGH40010F to simulate and fabricate a new HT class E PA.The test shows that the power-added efficiency(PAE)is 67.7%,and the drain efficiency(DE)is 74%;2.Theoretical research on broadband class E PA.Aiming at the problem that the traditional factorial factor cannot realize the bandwidth expansion of the new HT class E PA,the reason for the frequency band expansion of the continuous class F,F^-1,and J PAs is deeply studied and analyzed,and a generalized factorial factor(?+?sin(?+?)),which provides a greater degree of freedom for the realization of broadband high-efficiency PA design,and also lays a theoretical foundation for the realization of a new continuous class E PA.As a verification,a new continuous class E PA was simulated and fabricated.Tests show that:in the 2.5-3.6 GHz frequency band,DE is 54.6-66.9%;3.Theoretical research on broadband high back-off DPA.Based on the above work,a DPA is designed and fabricated by using the new continuous class E PA as the main power amplifier and the continuous class C-HT₃ PA as the auxiliary power amplifier.Tests show that:in the 3.0-3.8 GHz frequency band,when the output power is backed off by 8d B,the DE is 37-46.5%and the gain is 8.9-13.1 d B.The thesis work has certain reference value for the theory and application of PA.