| The increasing development of wireless communication system affects all aspects of communication industry,and the most important influence is the emergence of new wireless communication standards.This series of new standards put forward higher requirements for RF front-end components to meet the needs of different industrial applications.RF power amplifier is a key module in broadband or multi-band system,and its performance has great influence on the performance of the whole system in terms of bandwidth,output power and efficiency.Under the current development trend,on the one hand,in order to pursue broadband and high-efficiency power amplifiers,switching power amplifiers such as Class E and Class F power amplifiers are widely studied;On the other hand,the diversity of communication modes requires that the power amplifier can work in different frequency bands at the same time,and the dual-band power amplifier has become a research hotspot.In addition,in order to improve the bandwidth of the dual-band power amplifier,various bandwidth increasing structures have been put forward one after another,with the goal of expanding the dual-band point to dual-band while ensuring high efficiency,high gain and high output power.Therefore,in this paper,the power amplifier unit module under the new wireless communication standard is designed and studied by combining the switching type F high-efficiency power amplifier theory,dual-frequency theory and bandwidth expansion structure.Firstly,a large number of literatures about RF power amplifiers at home and abroad are consulted,and the research status of high-efficiency broadband class F power amplifiers and dual-band power amplifiers is summarized.Secondly,it introduces the classification of RF power amplifier and the technical indexes to evaluate the performance of RF power amplifier.Then,the design theory of class F power amplifier is expounded in detail,which lays a theoretical foundation for the following RF power amplifier.Finally,combining the design theory with the new standard of wireless communication,three RF power amplifiers are innovatively designed from three aspects: high efficiency,broadband and dual frequency:1.In the aspect of high-efficiency power amplifier: this design is oriented to radar communication,and adopts parasitic compensation circuit at the output end,and its microstrip line adopts L-shaped topology structure to offset parasitic effect caused by actual transistor packaging when the frequency rises.In addition,the matching circuit adopts step matching method.The measured results show that in the frequency band of 2.1-2.3 GHz,the maximum additional power efficiency of the power amplifier based on parasitic compensation circuit and step matching is 61.3%,the power gain is more than 12 d B,and the output power exceeds 40 d Bm.2.In the aspect of high-efficiency broadband power amplifier: this design is based on Class F power amplifier and faces the 4G communication base station.It combines the harmonic control circuit with the input and output parasitic compensation circuit,and at the same time reduces the parasitic effect of transistors,matches the second harmonic and the third harmonic to the corresponding impedance points.In addition,the bandwidth expansion structure is innovatively added to improve the phenomenon that the fundamental and harmonic frequency bands overlap,so that it can achieve high efficiency in a wider frequency band.The measured results show that in the frequency band of 1.1-2.5 GHz,the output power exceeds 40 d Bm,the drain efficiency exceeds 60%,and the gain is 9.3-14.4 d B.3.In the aspect of dual-frequency broadband power amplifier: this design is based on Class F power amplifier and faces 5G communication,innovatively combining the bandwidth expansion structure with dual-frequency harmonic control circuit,and expanding the bandwidth to 200 MHz at two frequency points.The measured results show that in the frequency band of3.3-3.5 GHz,the output power exceeds 41.5 d Bm,the drain efficiency is maintained at 71-75%,the additional power efficiency is 61-70%,and the gain is between 11.6-11.9 d B.In the frequency band of 4.8-5.0 GHz,the output power is above 39.5 d Bm,the drain efficiency is 65-70%,the additional power efficiency is 58-64%,and the gain is greater than 9.7 d B.The three RF power amplifiers designed in this paper,based on the new indicators of wireless communication,have reached the design indicators in terms of bandwidth and efficiency,providing a new idea for the subsequent power amplifier design. |
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