Design And Implementation Of The High Frequency System And Input Output System Of C Band Multi-beam Klystron

As one kind of vacuum electronic devices, klystron, with its high power, high gain, high efficiency, wide bandwidth and other characteristics, is widely used in the fields of radar navigation, detection and irradiation, microwave communication, television broadcast, space exploration and etc. With the development of fundamental research of klystron theory and application of a series of advanced technologies such as extended-interaction, output cavity loaded filter, stagger tuning and etc., klystron will have higher power, wider bandwidth and higher stability; accordingly, the improved klystron indexes are promoting the development of related industries. According to the number of the electron beams, there are two types of klystrons, single beam klystrons and multi-beam klystrons. In recent years, multi-beam klystrons undertake a rapid development and application due to its technical advantages in decreasing the voltage and expanding bandwidth.The high frequency system and input output system are two important parts of the multi-beam klystron and their structures and characteristics have a decisive influence on the klystron’s output power, efficiency, bandwidth and gain. Based on the actual klystron manufacturing demand, this paper studies the implementation of 500 MHz output bandwidth at 200 kW peak power level. In this study, a series of experiments are carried out and samples are made and tested.With the rectangular resonant cavity of C band based models as the research object, using HFSS 3D electromagnetic simulation software, this paper presents the field distribution, the resonant frequency and the characteristic impedance value in working mode, analyzes the influences on resonant frequency and characteristic impedance value of cavity volume, the number of electrons, the gap distance and end head’s cross sectional area, draws the optimal structure of rectangular resonant cavity of C band based models.According to the optimization rules of C band based mode rectangular cavity, with the help of computer simulation technique, this paper designs the structures of TM210 and TM220 rectangular cavity, analyzes the indexes to be achieved, determines the work mode and resonant cavity size.Using extended-interaction and filter loading technology, this paper realizes 500 MHz output bandwidth with the help of computer simulation and outputs 200 kW microwave energy under the protection of the beryllium oxide output window. This paper describes how to achieve a cluster bandwidth using the small signal and large signal simulation program to determine the number of resonant cavities, resonant frequency, quality factor and other parameters. With the design and simulation results as guidance, klystron is made and tested. The test results and simulation values are compared to verify the feasibility and accuracy of design.