Co-simulation Study On The Electricity,Heat And Structural Characteristics Of The High Power Microwave Window

The microwave window includes input and output windows,is one of the key components of vacuum electronic devices.The microwave window has two functions: one is to isolate the vacuum in the tube from the outside atmosphere,the other is to allow the internal/external signal of the tube be transmissed to the outside/inside without loss.As it allows the signal to be transmitted from one side to the other,sometimes the microwave input window and the microwave output window are not to be distinguished,generally referred to as the output window.The development of microwave windows is accompanied by the development of microwave vacuum devices.Ever since microwave tube was invented last century,it has been developed in the direction of higher frequencies and higher power capacity so as to meet people's growing demand in industrial applications and scientific research.As for the performance of the output window,good or bad,will directly affect the whole tube in gain,bandwidth,interaction efficiency between the electron beam and electromagnetic waves and power capacity,and so are the system reliability and life.In many cases,especially when the output power becomes relative large,the microwave window's broken will be the bottleneck of the power capacity of the whole microwave system.In the past,the study of microwave window is mainly through the analysis of its electrical properties to carry out structural design,the high power state when the window is heated is a rough description,the co-simulation on the electrothermal analysis of microwave window is also relatively less.And it lacks the consideration of the impact of feedback on electrical parameters after heat distortion of the microwave window.However,in the high-power state,the excessive accumulation of heat is likely to cause damage to the microwave window,and even have a great negative impact on its electrical properties.Therefore,it is of great practical significance to study the co-simulation of high power microwave windows.This dissertation combines the theoretical analysis and the computer simulation methods,through the basic theory of microwave window,the corresponding design of the high peak power and high average power microwave window is made and the cosimulation analysis is carried out to meet the design requirements.The main work and innovations of this dissertation are as follows:1.This paper deeply studies the design methods of microwave window,and systematically expounds the mechanisms of its damage.On the main points of the design,especially in improving the power capacity and avoiding the damage of the window,this article makes a detailed discussion and summary of various feasible design schemes.2.As regards the research method,we use ANSYS Workbench to achieve a cosimulation of electromagnetic fields,heat,force and deformation.In this way,the loading of the loads and the simulation process will be more accurate and complete,so the design of the microwave window has a better guiding significance.3.Aiming at the application of high peak window,the microwave window of the high peak power with a conical-shaped window structure is designed,and the influence of the relevant structural parameters on the transmission characteristics is analyzed,and the further study of the thermal characteristics is carried out.By comparing with the conventional pill box,which embodies the superiority of the conical-shaped window.4.Aiming at the application of high average power window,through mapping the design parameters of three-layer window to five-layer window,a design method of fivelayer dielectric microwave window with excellent heat dissipation and large bandwidth is proposed,and verifies the effectiveness and feasibility of the method.