Research And Design Of Novel Class-F Power Amplifiers Based On GaN

As the core component,the performance of power amplifier directly determines the system quality of entire communication base station.Therefore,the research on perfermance improvement of power amplifier has become hot and also chanllenging.This thesis focuses on the research on the class-F power amplifier,proposes three novel ones,i.e.,a broadband high-efficiency power amplifier,a tri-band power amplifier and a dualband power amplifier.Based on proper understanding and applying the general operation mechanism of power amplifier,utilizing advanced design method and exploring novel topologies,the power amplifiers proposed in this thesis outperform those reported in other literatures.The main research work of this thesis is summarized as follows:(1)An ultra-wideband power amplifier with a working frequency band of 0.3 GHz-2.0 GHz is proposed.It overcomes the problem that the output impedance changes drastically with frequency in the broad working frequency.The output impedance matching at multiple frequency points in the working frequency range is realized.Also,the curve of output impedance in the 0.3 ～2.0 GHz satisfies the high-efficiency impedance space obtained by the multi-harmonic source-load pulling.At the same time,the control of the output second harmonic is realized.The simulation and measured results agree well.When the input power is 28 dBm,the proposed power amplifier achieves 60.8%～66.4%drain efficiency(DE),a saturated output power of 37.6～41.8 dBm and a gain 9.6～13.9dB in the design frequency band 0.3-2.0 GHz(with 147.8% relative bandwidth).(2)A novel dual-band power amplifier topology is proposed.This dual-band power amplifier is designed for 5G application frequency bands divided by the three major operators of China Communications.The center frequencies of the two frequency bands are 2.6 GHz and 3.5 GHz,respectively.The design principle of the dual-band matching network is discussed in detail.Finally,one dual-band power amplifier example is verified and tested by experiment.As the measured results show,the maximum leakage efficiency at 2.6 GHz is 70.2%,the gain is 13.5 dB,and the saturated output power is 42.5 dBm;the maximum leakage efficiency at 3.48 GHz is 69%,the gain is 12.1 dB,and the saturated output power is 41.1 dBm.Compared with similar devices reported in related literatures at home and abroad,it has obvious advantages in performance.(3)A novel tri-band power amplifier topology is proposed.The three center frequencies of this power amplifier are at 0.9 GHz,2.3 GHz and 3.4 GHz respectively.Through the use of a new dual-band load stub network combined with a single-band matching circuit,the impedance matching at the above three frequency points is realized,and the second harmonics are controlled at the same time to obtain higher efficiency.Finally,the measured results show that the maximum leakage efficiency at 0.9 GHz is67%,the gain is 12.2dB,and the output power is 40.3dBm.The maximum leakage efficiency at 2.3 GHz is 71.7%,the gain is 12.6 dB,and the output power is 41.6 dBm.The maximum leakage efficiency at 3.4 GHz is 66%,the gain is 12.9 dB,and the output power is 40.9 dBm.Compared with similar devices reported in relevant literatures at home and abroad,it has obvious advantages in bandwidth.