Research On Key Techniques Of Cascaded Dual-Band High-Efficiency RF And Microwave Power Amplifiers

A radio frequency(RF)power amplifier(PA)is the most critical module in the RF front end of wireless transmitters,and its research has been the focus of RF/microwave communication techniques.Throughout the history of RF PAs,the research of RF PAs is mainly focused on how to improve the PAs' performance in various aspects.On the one hand,in order to improve the PAE,the high-efficiency PAs,such as class-E,classF and inverse class-F,have become one of the hot research issues in recent years.On the other hand,in order to support the transmission of high bit rate signals and multiple communication standards,the research of dual-band RF PAs has attracted more and more attention.In addition,in order to improve the gain of the dual-band highefficiency PAs,the cascaded dual-band high-efficiency PA is supposed to be the best solution.However,there are some important challenges in the implementation of these three circuits.Therefore,this dissertation focuses on these three aspects of the hot issues to be solved,and starts from the research of the high-efficiency PA,then researches the design method of the dual-band high-efficiency PA under this premise,and the key design techniques and design methods for the cascaded dual-band high-efficiency PA are researched in depth based on the above two aspects of the research,finally.Hence,the main creative works of the dissertation include the following three aspects:1.In terms of the high-efficiency RF PAs,two kinds of microstrip-line parasiticcompensation circuits are proposed for the class-F/inverse class-F harmonic-tuned PA and the parallel-circuit class-E switch-mode PA respectively,which not only have the compact circuit structure,but also solve the problem that the parasitic effects introduced by the transistor package have a significant influence for the efficiency of the highefficiency PA with frequency increasing.A class-F PA and an inverse class-F PA implemented based on the proposed parasitic compensation circuits achieve the maximum PAE of 80.2% and 79.1% at 2.14 GHz,respectively.2.In terms of the dual-band high-efficiency RF PAs,under the premise of the above research,a design method for the dual-band class-F high-efficiency PA is proposed based on the dual-band DC biasing-line with harmonic tuning and the composite left/right handed transmission line(CRLH-TL),which solves the problems of the lower PAE of the dual-band high-efficiency PAs than the single-band and the unbalanced performance of the two distinct operating frequency bands.A dual-band class-F PA implemented baseded on the proposed method achieves the maximum PAE of 78% and 77.1% at 1.7 GHz and 2.14 GHz,respectively.3.In terms of the cascaded dual-band high-efficiency RF PAs,under the premise of the above two aspects of the research,a design method for the cascaded dual-band harmonic-tuned PA based on dual-band inter-stage coupling technique and inter-stage multi-harmonic impedance matching technique is proposed,which fills the blank of the circuit design of cascaded dual-band high-efficiency PAs to some extent.Based on the proposed method,a cascaded concurrent dual-band harmonic-tuned PA operating at 1.6 GHz and 2.08 GHz is designed,where the power stage and the driver stage are designed to operate under dual-band class-F conditions and dual-band inverse class-F conditions,respectively.The measurement results show that the designed cascaded dual-band harmonic-tuned PA achieves the maximum PAE of 71.5% and 73% and the power gain of 23.2 and 22 d B at 1.62 GHz and 2.14 GHz,respectively.To the author's best knowledge,the implementation of the two-stage concurrent dual-band highefficiency PA is reported for the first time in the open literature.