Research And Implementation Of High Efficiency RF Power Amplifier

As the core component of RF module,RF power amplifier is widely used in Internet of things,energy transmission,communication,radar,detection and other fields.As the largest energy-consuming component of various types of RF modules,its power output capability and conversion efficiency will directly have a significant impact on the performance of the entire RF module.How to achieve higher efficiency when the RF power amplifier outputs the maximum power has become an important research content of current high-efficiency RF power amplifiers.This paper focuses on high-efficiency Class-F power amplifiers.Through comparison and analysis of current literature research results,it is found that narrowband Class-F power amplifiers still have problems,such as difficulty in debugging,low circuit quality factor and difficulty in achieving higher efficiency;while the relative bandwidth of broadband highefficiency Class-F power amplifiers is still difficult to exceed 50%.Aiming at the above problems,this paper proposes the following solutions:Research on narrowband Class-F power amplifiers:(1)Propose a new type of hybrid harmonic suppression network design method.By comparing and analyzing the advantages and disadvantages of the harmonic suppression network designed by traditional lumped parameter components and distributed parameter components,using mixed design ideas to combine the advantages of the two components,the harmonic suppression network of narrowband Class-F power amplifiers can improve the overall circuit quality factor,high reusability and easy to achieve the circuit performance.(2)Propose a design idea of a combined matching network that realizes harmonic suppression and fundamental wave matching at the same time.This method can realize the common matching of harmonic impedance and fundamental impedance in a limited PCB area.This paper applies this structure to the design of the input network of the Class-F power amplifier,so that the input end of the Class-F power amplifier also has the function of suppressing harmonics,further improving the Q value(quality factor)of the overall circuit,and the combined matching network avoids the problem of excessive PCB area.Research on broadband Class-F power amplifiers:(1)Propose an improved continuous Class-F mode analysis method.By using the idea of continuous Class-F power amplifiers,narrow-band class F power amplifiers have broadband characteristics.In this paper,based on the traditional analysis based on the Class-B bias mode,the consideration of different conduction angles of transistors is added,which makes the bias analysis of the continuous Class-F mode more perfect.At the same time,based on the derived continuous Class-F voltage and current waveform expressions,a new variable coefficient expression that can control the waveform is introduced,so that the fundamental,second harmonic and third harmonic impedance values has been expanded to include conduction angle information.Forming a new and improved continuous Class-F mode analysis method is suitable for broadband amplifier design.(2)A design method for output matching network of wideband Class-F power amplifier is proposed.Based on the impedance conditions of the improved continuous Class-F mode,combined with the design idea of the combined matching network and used the broadband characteristics of the sector line to replace part of the straight stubs,the output matching network structure of a broadband Class-F power amplifier is designed.The characteristics of the Class-F power amplifier have been realized in a wide frequency band.Based on the design methods mentioned above,this paper designs and implements a narrowband Class-F power amplifier working at 2.4 GHz frequency and a wide-band Class-F power amplifier working at 1.8-3 GHz frequency band.Through theoretical derivation,principle analysis,software simulation and actual debugging,the design ideas and processes of the two power amplifiers are discussed in detail.And by comparing and analyzing the test data,it verifies the scientificity and feasibility of the method proposed in this paper.