Simulation Study On X-band And C-band High Power Klystron

Klystron is a well-developed microwave vacuum devices.By using the speed and density modulation principle convert electrical energy to microwave energy,it has high gain?high efficiency and high power output characteristics.In terms of dual-use,it has a broad application prospect.Combined by MAGIC?CST?CHIPIC and other software.The theoretical analysis and computer simulation are carried out for the X-band TM₃₁₀10 multi-injection klystron and C-band TM₀₁₀10 single-injection klystron.The whole tube was studied comprehensively.The principle of velocity modulation?density modulation?clustering phenomenon and theory are analyzed.The principle of induction current and the theoretical space charge wave of small signal are analyzed.This paper also described the theoretical part of large signal,including point-to-point model and disk model.These are important components of klystron theory.In this paper,the main properties and parameters of the electron gun are analyzed,including the conductivity of the electron injection,the density of the electron injection,the compression ratio of the electron gun and the cathode emission surface density.The paper also expatiates on the collection of poles,mainly including the causes of electron backflow and the methods to suppress the electronic reflux.The input voltage is 42kV and the current is 18A.The flow coefficient is 2.3?p and the laminar flow has a good perfermence.The design of the electron gun meets the requirements.The multi-injection klystron collector of X-band klystron injection are researched.The design that the slope of the collector slope is 0.146.The length between the output cavity and collector is 12mm.In this case,the electronic return little.Cavity is an important part of the high frequency of interaction.By using CST,the intrinsic frequency of the resonant cavity was studied.The main research have a influence on cavity gap among drift tube head?cavity radius and cavity height.By using CST,the quality factor of resonant cavity was studied.The main research have a influence on cavity gap among drift tube head?cavity radius and cavity height.By using CHIPIC particle simulation software,the influence of frequency on output power and the influence of resonator radius on output power are analyzed.This paper also analyses the influence of magnetic field which is focused on the role of the system.Only in the axial magnetic field,the electron injection can't good focus.In the case of meeting the brillouin function,electronic note passing rate is good.There will be a small amount of electrons on the pipe wall.The study found that the electronic Angle to speed has a great influence on space charge force of electronic injection.After adding the radial magnetic field,the electronic injection rate is increased.The electronic injection laminar and the performance of the klystron is good.Finally,we use the CHIPIC unique 3-D simulation modeling interface for X-band multi-injection klystron and C-band single klystron.The size and the structure of the importance is taken into account.By using non-uniform grid,the computer memory is rational utilizated and the thread parallel numerical simulation method is adopted.For simulation of the whole pipe,the frequency of X-band multi-injection klystron is9.75GHz.The input power is 23W.The output peak power is 123kW.The average power is 57kW.The efficiency is about 34.7%and the gain is about 37.28dB.The normalized frequency of C-band single klystron is 1.The input power is 32W and the output normalized frequency is 1.The peak power is 300kW and the average power is150kW.The bandwidth is about 50MHz.The efficiency is about 39.8%.The gain is about 40dB.