Ridge Loaded Disk-loaded Waveguide Slow-wave System

Travelling wave tubes (TWT) are the heart parts of radar systems,communication systems,electronic countermeasures,remote-control&test device,accurate guidance equipment,etc.As the main component of the beam-wave interaction of a travelling wave tube for producing microwave energy,the solw-wave structure ( SWS ) is the key of the TWT. It basically determines the performance of the TWT . In this paper, the coaxial disk cylindrical waveguide with longitudinal ribs as SWS, a series of detailed studies have been made by theoretical method combining with numerical ananlysis,and a great deal of valuable conclusions have been obtained. Our main and creative works are as following:1. First, on the basic theory of the coaxial disk cylindrical waveguide, we analysis field equation in each area of the coaxial disk cylindrical waveguide with longitudinal ribs. The dispersion equation and the coupling impedance of this structure are obtained by means of triangle function's orthogonality and combing with the field matching method. Through the numerical calculation, we discuss the influence of various structure's parameter on the dispersion and the coupling impedance. It shows that the coaxial disk cylindrical waveguide with longitudinal ribs, which is one of large diameter, all-metal structure and allows for high average power capability, can improve the propagating wave's characteristics and gain a relative broad bandwidth by means of modifying the geometrical dimensions of the circuits. 2. Linear theory of the beam-wave interaction in the coaxial disk cylindrical waveguide with longitudinal ribs has been studied. We consider the solid electron beam. The hot dispersion relation including the electron beam space charge effect is obtained in this paper, by series of propagating with using of the boundary condition and combining with the field matching method. As a high-power TWT, we consider the relativistic effect of the solid beam. The numerical results are given in terms of thesmall signal gain curve and slow-wave ration curve. Finally, the influence the radius of the electron beam, current of the electron beam, the acceleration voltage and the geometrical dimension of the slow-wave structure on small signal gain are discussed. Studies show that: there exists an optimum beam voltage for the maximum gain; the gain increases with the beam current;　the beam radius effects the gain intensively; we can gain both high power output and relative broad bandwidth by choosing the number of ribs and appropriate beam parameters.