Research And Design Of RF Power Amplifier Applied To IoT Communication

With the comprehensive opening of the fifth generation mobile communication mode,the high-speed,reliable and large-capacity communication network stimulates the rapid development of various application technologies and promotes the evolution of the intelligent society of industry and life.As one of the important technologies of 5G communication,the communication technology of Internet of things is no longer limited to the data exchange of various devices in a small range,but to improve the coverage range and carrying capacity with the help of the huge cellular communication network.The communication technology of cellular Internet of things will enter the stage of rapid progress.The cellular network depends on various base station devices as communication nodes,which requires the base station to realize stable and low-distortion signal transmission.In the base station transceiver module,the rf signal power amplifier in the launch is at the end of the link of the level.In order to provide enough power,power amplifiers are strongly nonlinear devices at the same time,the base station communications equipment usually has strict linearity requirements.Thus improving the power amplifier linearity becomes the hot research topic.This paper studies and designs the power amplifier for the communication of Internet of things base station.Firstly,the research background of linearization technology at home and abroad is introduced.Then,the advantages and disadvantages of Ga As HBT process devices are analyzed from the material and device models of rf power amplifiers.This paper introduces the relative indexes of power amplifier and the traditional power amplifier type,expounds the nonlinear effect of power amplifier,and introduces the power fallback,feedforward,feedback and pre-distortion linearization techniques.Finally,Ga As HBT process is adopted to design a two-stage power amplifier with operating frequency between 860MHz and 894MHz,which has a high saturated output power and meets the rated power requirements of the power backout line.The negative feedback structure is used to improve the stability and linearity of the power amplifier,and the harmonic processing circuit is added to the output matching circuit for efficiency optimization.In the bias circuit,the self-adaptive bias structure is used to suppress the influence of temperature change on the working state of the transistor,and the stable amplifier enables it to be biased in the working state of linear amplification.The design layout and the substrate were simulated jointly to optimize the device parameters and circuit performance.Finally,the test board was made in the packaging test phase and the performance test platform was built with the instrument.The test results show that the output power P_{1d B} of the 1d B compression point of the designed power amplifier was 34.7d Bm,with a power gain of 30.7d B.At the same time,before the output power reaches P_{1d B} the maximum distortion of the power amplifier gain was 0.52d B,and the maximum phase distortion of the output signal was 0.32°.When the output power back to 24.5 d Bm rated power output,the power amplifier power added efficiency was about 13.6%,ACPR for 47.4 d Bc.The test results show a desirable performance.