Research On Power Amplifier Linearization Technology Applied To 5G System

Nowadays,5G,the fifth-generation mobile communication,has become the main research field in the wireless communication industry.In order to achieve high-speed signal transmission in the 5G era,whether it is to increase the spectr?m utilization or to broaden the spectr?m bandwidth;this requires that the core component of the communication system,the power amplifier,still has a high linearity when it operates in a strongly nonlinear area.Therefore,this article focuses on the power amplifier linearization technology:the analog pre-distortion circuit embedded in the amplifier,and analyze its basic principles and impact on the power amplifier.The main research content of this article is as follows:This paper analyzes the basic principle of an analog predistorter based on pHEMT;using the pp-25 process,two power amplifiers working at 16-18GHz are designed;one is a two-stage cascaded power amplifier,and the other is a pre-distortion circuit based on the first one.The test results show that the output power of the two power amplifiers is greater than 20dBm,the gain is better than 20d B,and the power-added efficiency is greater than 28%.Under the excitation of dual-tone signals??f=10MHz?,IMD3 with the3dB saturated power back-off point can improve 6-8dBc.Therefore,the pre-distortion circuit can be integrated in the power amplifier;and the power amplifier linearity can be improved without affecting the performance of the power amplifier.In this paper,a detailed analysis of the improved cold-FET pre-distortion circuit is performed,and a diode cold-FET pre-distortion circuit is selected to enhance the linear improvement of high-power amplifiers.Based on the pp-15 process,two designs of power amplifiers working at 25-30 GHz were completed.The main difference between the two power amplifiers was whether or not a predistortion circuit was added.Comparing the simulation parameters of the two power amplifiers:The saturation output power of the two power amplifiers is greater than 28.5 dBm.At this time,the power-added efficiency is greater than 30%and the gain is 23 dB.After the predistortion circuit is embedded,the small signal gain of the power amplifier is reduced by 2.5dB,while the saturated output power is unchanged,the output power at the 1d B compression point is increased by0.7dBm,and the power added efficiency is slightly increased by 1%;the OP_1dB of the two power amplifiers varies by about 1.5 d B in the 5 GHz bandwidth;and the output power is from 0dBm to 17dBm,IMD3 is lower than 37dBc;In 26-29GHz,IMD3 can be improved by 15dBc in the nearby of 3dB back-off.Therefore,a power amplifier with a diode cold-FET predistortion linearization circuit satisfies the design requirements,and this predistortion structure can improve the nonlinear characteristics of the power amplifier.