Research On Design Methods Of High Efficiency RF Power Amplifier

As we all know,efficiency is a very important performance index to measure the performance of wireless communication systems,and RF power amplifiers are the most critical devices that determine the efficiency of wireless communication systems.Therefore,how to realize the design of high-efficiency RF power amplifiers has been a hot research topic in the field of communications.In recent years,more and more attention has been paid to harmonic tuned amplifiers and switching power amplifiers because they can achieve high efficiency while maintaining high output power.In addition,the integration of multiple devices into a multi-functional device by the way of multi-component collaborative design can well meet the current development trend of miniaturization and high integration of communication system,and can reduce many additional losses.Therefore,it is also of great research significance to improve the efficiency of the power amplifier indirectly through the method of collaborative design.In this dissertation,the design method of high efficiency harmonic tuned power amplifier is studied firstly.Based on the technology of harmonic load-pull and the large signal dynamic load-line model of transistor CGH40010 F,a harmonic tuned power amplifier with 2GHz working frequency,38.69 d Bm output power and 81.53% drain efficiency is designed by ADS simulation.And the power amplifier has been fabricated and tested,and the test results are in good agreement with the simulation results.At the same time,in order to further verify the effectiveness of the harmonic control method to improve the efficiency of power amplifier.The design method of class-F power amplifier with the same harmonic control characteristics is studied.And based on the technology of load-pull,harmonic control and parasitic compensation,a class-F power amplifier with 2GHz working frequency,41.25 d Bm output power and 79.07% drain efficiency is designed.In addition,based on the actual situation that power amplifier and filter usually work together,in order to improve the efficiency of the power amplifier indirectly,this dissertation proposes to design a class-F filtering power amplifier based on the method of collaborative design.Firstly,based on the synthesis theory of the coupling matrix of the generalized Chebyshev filter,two methods are proposed to synthesize the coupling matrix of the output matched filter with the functions of impedance conversion and signal filtering.Then,according to the coupling matrix,a microstrip output matched filter is synthesized and designed.Finally,the output matching network of class-F power amplifier is replaced by the microstrip output matched filter,and a class-F filtering power amplifier with output power of 40.54 d Bm and power added efficiency of 60.44% is designed.The simulation results show that,compared to the traditional method of filter plus power amplifier,the filtering power amplifier designed based on the method of collaborative design improves the efficiency by about 5% and the output power by about 1d B.