| When proper plasma is introduced into microwave vacuum electronic devices, the limitation of current due to space charge effect of electron beam can be eliminated, the beam power and output power of microwave are increased greatly , which provides a new approach for the development of microwave vacuum electronic devices.Extended interaction oscillator (EIO) is an important class of millimeter wave vacuum devices, widely used in millimeter wave radar and telecommunications, which combined high-gain broadband characteristics of the traveling wave tube with the advantages of high efficiency of klystron up. It is a new device of both a high gain and efficiency and sufficient bandwidth.In this thesis, the EIO filled with plasma is studied and main works as following:1. Linear and nonlinear theory of wave interaction in the slow wave system filled with plasma is studied; the dispersion characteristics and growth rate are obtained.2. The transmission characteristics of electron beam in plasma are studied, it is found that plasma can improve the transmission characteristics of beam and the focusing magnetic field to sustain beam transmission can be decreased greatly.3. MAGIC program are used to simulate three kinds of EIO: hollow beam, solid beam and coaxial, the plasma is found to have great influence on beam-wave interaction, plasma waves can be excitated by e-beam, under some circumstances, plasma can increase the output power and operating frequency of devices.4 According to the results of simulation, a 8 mm EIO with hollow cathode plasma electron gun is designed, fabricated and tested, the preliminary experimental results are obtained. |
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