Research And Design Of Broadband High Efficiency Power Amplifier With Continuous Class Operation Mode

As an important part of the wireless transceiver system,the power amplifier directly plays a decisive role in the performance and operation of the overall communication system.As an indispensable and important component,the power amplifiers must meet various specifications such as bandwidth,efficiency and linearity,these specifications significantly complicate the design of power amplifiers.This thesis will expand the bandwidth and improve the efficiency to adapt to the modern communication system based on continuous class power amplifier and Doherty power amplifier with high back-off efficiency.The main research contents of this thesis are as follows:1.Research on the continuous class F/F^-1 power amplifiers systematically by introducing waveform parameters?and?to the voltage and current waveform expressions of standard F/F^-1power amplifiers,then the fundamental and harmonic impedance regions of the current source plane of the continuous class F/F^-1 power amplifier are derived.The S-parameters of the package model based on the Z-matriare can be obtained to calculate the package surface impedances,and combined the optimal load impedances are determined by the load-pull technique.Finally,a continuous class F^-1 power amplifier is designed with a low-pass filter network,which measured results show that the saturated output power is about 39.3-42 dBm,the gain is about 16 dB and the saturation efficiency is between 59-74%in the 2.0-4.0 GHz band.2.An improved continuous class F Doherty power amplifier is proposed by combining the continuous Class F power amplifier with bandwidth expansion capability and high saturation efficiency and the Doherty power amplifier with high back-off efficiency to realize the broadband and high efficiency Doherty power amplifier.The output matching networks are designed based on Z-matrix two-point matching method,which omitting the traditional quarter-wavelength line,and strictly controlling the phase shift of the output matching network to expand the bandwidth of the Doherty power amplifier.The peaking output matching network is designed by using quasi-elliptic low pass filter matching network to improve the saturation efficiency and output power of the peaking amplifier,and reduce the influence of the second harmonic impedance modulation of the carrier amplifier.In the post-matching network,the carrier amplifier back-off and saturation harmonic impedances are be controlled to achieve high efficiency.Finally,a broadband high efficiency continuous class F Doherty power amplifier is designed to verify the feasibility of the above methods.The measured results show that the saturation output power is 43.2-44 dBm,the saturation efficiency is 53-66%,the gain is about12.5 dB,and the 6 dB back-off efficiency is between 53-58%in the frequency range of 1.65-2.85GHz.When driven by wideband modulated signal and after digital pre-distortion,the Doherty power amplifier shows excellent linearity.In this thesis,the designed high-efficiency power amplifier is physical processed and measured,and the measured results are basically consistent with the simulation results which verify the theoretical and research programs in this thesis.The research in this thesis provides a reference for designing broadband high efficiency power amplifiers.