随着通信技术的发展，功率放大器线性度要求日益提高。该文提出一种两支路预失真电路，在单支路预失真电路基础上加入可调衰减器和非线性发生器级联成的辅助支路，改善了单个非线性发生器增益曲线斜率不足的问题，并在ADS中代入行波管模型仿真分析。在此基础上，加工Ku波段实际预失真电路并与行波管联合实验，线性化后的行波管放大器三阶载波交调比在输入功率回退3 dB时达到12.92 dB，回退6 dB时达到22.8 dB，线性度有了明显的改善。%With the development of communication technology, the requirements of power amplifier linearity are increasing. This paper presents a kind of two-branch predistortion circuit which contains the main branch and the auxiliary branch. The main branch is a diode based nonlinear generator and the auxiliary branch consists of variable attenuator and nonlinear generator. Compared with single nonlinear generator, this two-branch predistortion circuit increases the slope of amplitude characteristic. The ADS co-simulation of Traveling Wave Tube Amplifier (TWTA) and new predistorion circuit show the improvement of linearity. Based on the analysis and simulation, a Ku-band practically predistortion cuicuit is designed and tested with the TWTA. The results of experiments show that, the Carrier to Intermodulation (C/IM3) at TWTA Input Power Back Off (IPBO) of 3 dB can reach 12.92 dB, C/IM3 at TWTA IPBO of 6 dB can reach 22.8 dB. With the linearizer, the linearity of TWTA is clearly improved.
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