Research Of Key Technologies For High Efficiency Dual-band/Broadband Power Amplifier

With the evolution of the modern microwave wireless communication technology,the wireless communication systems are expected at the multiple frequencies and multiple modes in terms of diverse signals and wireless standards.A low-power wireless communication system which can operate at multiple frequencies concurrently and contains a single-channel transceiver system is very competitive.As the most important power device in receiver RF,the increase of power amplifier efficiency is of great significance to communication system.Meanwhile,wireless communication systems adopt spectrum-efficient digital modulation schemes,which lead to high peak-to-average power ratio(PAPR)modulated signals.In order to meet the linearity indicators of the system,power amplifiers need more power back-off,which will cause a decrease in efficiency.Therefore,the high PAPR signal needs to be clipped by crest factor reduction technology.The main focus of this thesis includes the analysis and design of high-efficiency dual-band/broadband power amplifiers and crest factor reduction for concurrent power amplifier.The main research results of this article are as follows:1.A series of concurrent modes is introduced.(1)A concurrent Class B/J continuum mode is presented.Concurrent Class B/J continuum mode provides more freedom and flexibility for design without output power and drain efficiency degradation.A 1.9/2.35 GHz dual-band power amplifier based on proposed concurrent mode is designed,fabricated and measured to verify the proposed theory;(2)Concurrent Class-F mode and concurrent continuous Class-F mode are presented.The concurrent Class-F mode significantly increases concurrent drain efficiency to 79.4%by introducing second and third intermodulation and harmonic matching.Then,a more generalized concurrent mode base on concurrent Class-F mode is proposed by introduce two independent design parameters,which is named as concurrent continuous Class-F mode.This concurrent mode provides a broader optimal design and maintains same performances as concurrent Class-F mode.A 1.88/2.605 GHz dual-band power amplifier is designed,fabricated and measured to verify the proposed theory;(3)A concurrent inverse Class-F mode is presented.When driven by two continuous wave signals with same amplitudes,the theoretical results show that the proposed mode show more than 3.8 dB output power promotion compared with concurrent Class-B mode.The concurrent inverse Class-F mode provides a method to design high output power concurrent power amplifier.2.A two-dimensional crest factor reduction(2D-CFR)is proposed to improve the dual-band concurrent performance of power amplifiers.The concurrent performances of target PA can be improved significantly when the power for peak detection conforms to the concurrent characteristic.Measured results show that the drain efficiency(DE)is improved from 34.0%to 36.6%with proposed 2D-CFR when compared with conventional 2D-CFR while maintaining similar error vector magnitude(EVM)and all ACPRs,which indicates a significant performance improvement.3.A generic method is presented for multi-octave power amplifier based on extended version of the continuous class-F.The theory allows resistive second-harmonic impedance and sacrifices part of efficiency to get a bandwidth over one octave.A 0.2-2.5 GHz multi-octave PA is designed and fabricated.Experimental results show the drain efficiency of 55.5-70.3%and the output power of 43.7-46.9 dBm across 0.2-2.5 GHz(170%).4.Two designs of high-efficiency power amplifiers with harmonic-tuned network are presented.(1)An analytic methodology for designing dual-band harmonic-tuned output matching network is presented.The proposed output matching network integrates harmonic control circuit and reduces the complexities of design and circuit structure.Besides,the second and third harmonics control are provided for two operated frequencies.In order to verify the method,a 1.8/2.65 GHz dual-band high-efficiency PA adopting a GaN HEMT is presented.Experimental results show the drain efficiencies of 76.2%and 71.6%at 1.8 and 2.65 GHz,respectively.In addition,the drain efficiency more than 65%can be maintained from 1.55-2.0 GHz and 2.65-2.8 GHz;(2)An inverse Class-F power amplifier based on dual transmission line(DTL)is presented.The output matching network with DTL has a simple and compact circuit topology compared with other harmonic-tuned OMNs with open/short shunt stubs and provides up to 6th harmonic suppression.Finally,a 2.4 GHz inverse Class-F PA is designed and fabricated.The.experimental results show the highest drain efficiency of 87.4%in the operating frequency.