Research On Permanent Magnetic Packaging Technology Of S-band Relativistic Klystron

When comparing the efficiency of high-power microwave devices,the power and energy required by the focusing system are often neglected.The energy,volume and weight consumed by these focusing systems that can generate magnetic fields are often larger than those of the high-power microwave devices themselves.Becoming less and less practical in engineering applications.The permanent magnet focusing system is only one-fifth to one-tenth of the traditional capacitive system in terms of volume and weight,and there is a more obvious advantage that the permanent magnet focusing system does not consume any power,so high-power microwave devices are made into permanent magnet packaging Later,it can expand its application range.This paper studies the packaging technology of S-band relativistic klystron permanent magnet.In the light of the structural features of the klystron device involved in this paper,two technical routes of uniform permanent magnet focusing system and periodic reversal permanent magnet focusing system are used for research.The main research contents of article are as follows:First of all,use the simplest magnetic circuit to derive the two basic equations for magnetic circuit calculation,compare the characteristics of various magnetic materials,select the appropriate magnetic material,and link the burden line with the demagnetization curve to determine the working point of the permanent magnet.Secondly,the transmission characteristics of the electron beam in the drift tube are studied.,the transmission theory of the multi-beam electron beam is deduced and the transmission channel is modeled,and then the electron beam transmission is simulated using the theoretical value as a guide,and the simulation results are analyzed.Third,through the magnetization analysis of the permanent magnet ring,obtain the advantages and disadvantages of axial and radial magnetization respectively,and then the brillouin magnetic field required for electron beam transmission is calculated,combined with the simulation of the klystron device,to determine The magnetic field conditions that can make the electron beam stable transmission,a uniform permanent magnet focusing system is designed and combined with device simulation.Simulation result display,the use of a uniform permanent magnet focusing system can make the S-band coaxial multibeam klystron at a voltage of 500 k V,a total current of 5k A,and a magnetic field strength of 0.35 T to obtain a microwave output power of 570 MW,which is close to the result under a constant magnetic field.Finally,in order to further explore the light weight,small size,and low energy consumption of the focusing system,the magnetic field generated by the radially magnetized permanent magnet ring has the characteristics of a reverse field,and multiple radially magnetized permanent magnet rings are combined.Using the characteristics of soft magnets,a periodic reversal permanent magnet focusing system is designed,and then the magnetic field configuration of magnetic system is optimized,and the affect of not the same parameter changes of the periodic reverse permanent magnet focusing system on the magnetic field is analyzed.So as to comprehend the affect of the magnetic field amplitude and the distance between the pole boots of the periodic reverse permanent magnet focusing system on the electron beam transmission,using simulation software,optimize the initial parameters of the periodic reversal permanent magnet focusing magnetic field,and obtain 25 sets of magnetic field results with different magnetic field amplitudes and different pole shoe distances.Bring the electron beam into 25 sets of results for simulation,and found that when the magnetic field amplitude is 0.13 T,the distance between the pole shoes is 140 mm,the voltage is500 k V,and the total current is 4.2k A.The multi-beam electron beam can be stably transmitted in the drift tube,it provides a design and experimental basis for the application of the subsequent periodic reversal permanent magnet focusing system in the coaxial multi-beam RKA.