Return Wave Oscillation In The Nonlinear Theory Of Traveling-wave Tube

Traveling Wave Tube (TWT) is widely used in modern military electronicequipments, such as communications, radars, electron warfare, etc. Stable operation of aTWT which affect the operational states of whole system is a fundamental requirementfor any application. BWO, which is based on interaction between electronbackward-wave and beam, is an important factor that influences the stable operation ofTWT, because BWO is inherent in the interior of TWT. With the power and the workingvoltage of TWT increasing, BWO appears easily. The work system will breakdown onceBWO generates. So it is necessary to restrain BWO. Attenuator is one of the parts ofTWT, which is used to improve the stability of TWT.In this dissertation, we made theoretical study and numerical simulation on twoimportant aspects in detail, i.e., the RF characteristics of helix slow wave structures withattenuator and backward-wave self-oscillation.Though domestic and foreign scholars had made abroad and deep research on helixslow wave structures, the research on helix SWS added an attenuator is lack. Since theattenuator is an indispensability part of helix slow wave structure, it is necessary toanalyze this structure. In this paper, we set up a model of helix SWS which isintroduced the attenuator. Then we achieved the dispersion equation and interactionimpedance, and analyzed the characteristics of this structure.The problem of backward-wave self-oscillation in helix TWT has been analyzedbased on nonlinear theory. This nonlinear method is more suitable for describing thephysical nature of the electron-wave interaction than the linear one, because theinteraction is a nonlinear process in nature. And the theory presented here can providetheoretic value and engineering sense for suppressing BWO and thus improvingstability of helix TWT.