Traveling-wave Tube Electron Optical Emission Model And Numerical Simulation Analysis

Traveling wave tubes (TWTs) are broadband, high power, high gain microwave/millimeter wave amplifiers, are widely used in communications, electronic warfare and radar systems. TWT electron optics system, which consists of electron gun, focusing system and collectors, deals with the generation, formation, sustentation and collection of electron beam, is the important part of TWTs. The quality of electron beam, which offered by electron gun, determines fundamentally the TWTs'crucial parameters such as efficiency, gain, working stability and noise characteristic etc. The MDC is used to collect the waster electron, improve the amplifiers efficiency and energy conservation. Using computer simulation and CAD technique is a significant way to ameliorate and optimize design for improving the TWT's crucial parameters. In this paper, some works have done to the"CAD technique of the electron gun"and"CAD technique of the multistage depressed collector"which are the subtopic of the 10th Five-year plan pre-study project of Wide Band High Power TWTs CAD. The main works and innovations of this paper are listed as follows:1,This paper summarized systematically and roundly domestic and foreign research actuality, up-to-date evolution and developmental direction of EOS CAD's technique; discussed the usual numerical calculation method in EOS CAD's domain; research and built up the basic equation of the TWTs'electron optics system, as well as the physic models and physic equations of the electrostatic field and magnetostatic field in the axial symmetrical system. In the meanwhile this paper built up the electron motion equation and the electron trajectory equation, which was in consideration of relativity correction;2,In order to reduce the error induced by the using of plane diode to make an approximate calculation for the pierce guns, the three-halves power equations considering the effect of the space charge for a spherical diode are derived from the possion equation. Apply the equations into the numerical simulation program, simulate series electron guns and compare the results with other electron optic software. In the meanwhile, associative with the experiment data, do a correction to the cathode emission current which was in consideration of temperature effects and relativity correction.3,Researched the secondary electron emission model. Considered the"true"secondary electrons, elastically scattered electrons, in-elastically scattered electrons emission yield, angular distributions, energy distributions. Through selecting some types materials for the electrodes, the simulating results have been compared between no secondary and secondary electrons. In the meanwhile, considered the secondary electrons secondary emission. Apply this secondary electron emission model into the numerical simulation program.4,Depend on the UESTC_GUN and UESTC_MDC, applied the research emission model into it. Design new numerical simulation program with C++ in the VC++6.0 platform and do a series simulation for checking.