中文摘要：

本文全面地研究了信号注入（谐波,三阶交调）对空间行波管（STWT）的五阶交调（IM5）失真分量的抑制情况。首次采用泰勒级数法对IM5理论分析,继而利用计算机仿真,分别注入谐波和三阶交调（IM3）信号来抑制STWT的IM5,并得出最大抑制量及最佳注入信号参数。实验结果表明：谐波和IM3都能够较明显地抑制IM5,IM3注入技术能够得到31.6 dB的IM5抑制量,大于谐波注入技术的最佳抑制量18.3 dB,且IM3注入功率也更低,实验条件较宽松,因此对窄带STWT而言,IM3注入技术比谐波注入技术能更明显地抑制五阶失真分量。

英文摘要：

This paper discusses systematically signal injection for reducing the fifth-order intermodulation（IM5） products in space TWT（STWT）.According to the research on theoretical analysis and computer simulation,the maximum IM5 suppression and best singal injection parameters are obtained by harmonic and IM3 injection respecively.The experimental results show that both techniques are available in suppressing IM5 product,and the IM3 injection perform better than second-harmonic injection in STWT.The maximum IM5 suppression can acheive 31.6 dB by IM3 injection,which is bigger than 18.3 dB by second-harmonic injection.The input-power of the former was far less than that of the latter,thus,the IM3 injection performs better than second-harmonic injection to suppress IM5 for the narrow-band STWT.