Coaxial Diaphragm Loaded Slow-wave System

With the progress of the modern military science and technology, 'High Power Microwave Technology' as a new field is developed rapidly. The key component of a high-power microwave device is the RF structure in which the beam and wave interact. To Traveling Wave Tube (TWT) .it is the slow-wave structure(SWS) which basically determine the performance of the TWT. In the dissertation, the coaxial disk-loaded cylindrical waveguide used in SWS of Relativistic Traveling Wave Tube(RTWT) is discussed .The types of the coaxial disk-loaded cylindrical waveguide and the coaxial ridge-disk-loaded cylindrical waveguide are all-metal slow-wave structures and have advantages of large size, good thermal conductivity ?high precision of manufacturing and assembling. Because the coaxial structure can broaden the bandwidth, they might be one type SWS of the high power capacity and the middle bandwidth .Several major and valuable achievements are listed as the followings:1. First, the theory of the coaxial disk-loaded cylindrical waveguide SWS is analysed, and the dispersion equation and the coupling impedance of this structure are obtained. Through the numerical caculation , it is discussed that the influence of various circuit dimensions on the dispersion and the coupling impedance.2. The linear theory of the coaxial disk-loaded cylindrical waveguide TWT is built and the dispersion equation with an annular electron beam of this TWT is obtained according to self-consistent field theory and the field matching method. The computation results of the hot dispersion equation indicate the relations between the electron beam parameters and the small signal gain.3. For the first time, the coaxial ridge-disk-loaded cylindrical waveguide as SWS is presented. Its dispersion equation and the expression of coupling impedance are given by application of the field matching method. A series of numerical results show that the influence of structure dimensions on the dispersion characteristics and interaction impendance. It suggested that the ridge-loaded structure can improve thecoupling impedance in a way .4. The 'hot' dispersion equation of the coaxial ridge-disk-loaded cylindrical waveguide TWT with an annular electron beam can be firstly obtained according to self-consistent field theory. The influence of various electron beam parameters on the small signal gain is investigated and discussed by the numerical results.5. The model of the coaxial disk-loaded cylindrical waveguide is manufactured to testify the dispersion properties of this structure. The experimental results are in good agreement with the theoretical results.