Simulation And Computing Of Cold Characteristic Parameters For Hughes Type Coupled-cavity TWT Slow-wave Structure

Traveling wave tube(TWT) is the most important vacuum device in modern electronic warfare because of its wide band, high efficiency, high power and other characteristics. TWT plays an important role as high power and wide band microwave generator and microwave amplifier. The higher requirement for TWT is also being promoted by modern satellite communication, space communication, phase array radar and etc, from the aspect of smaller size, longer age, and higher reliability and so on.TWT is divided into helix TWT and coupled-cavity TWT, Hughes-type coupled cavity TWT is currently widely used coupled-cavity TWT. It has high-power, high stability, good heat dissipation. These are the helix TWT can not be achieved. Its slow-wave structure(SWS) cold characteristic parameters including coupling impedance and dispersion characteristics. They are two very important cold parameters in research and design of the Hughes-type coupled cavity TWT. They decided the whole traveling-wave tube voltage, frequency bandwidth, efficiency and gain.The working frequency of TWT is very high; therefore, the size of TWT slow-wave structure is very fine. This brought much difficulty for the design. Nowadays,more and more computer simulation technology is brought into TWT design work for saving cost and improving design efficiency. It can be applied in each link of TWT design work.This paper introduces the definition of dispersion characteristics and coupling impedance, theoretical calculations. And describes the dispersion characteristics of the experimental methods: traveling wave method and the resonance method. Comparative and analysis of two experiments testing methods and choose the resonance method according to the actual conditions. Measuring dispersion characteristics of coupled-cavity TWT, get the Brillouin diagram, by using a vector network analyzer. Also introduced two measurement method to measure coupling impedance: resonant perturbation method and non-resonant perturbation method. CST Microwave Studio simulation software and HFSS Simulation Calculation can be used to modeling and simulation Hughes structure coupled-cavity TWT slow wave structure. This paper given the specific simulation methods and procedures, and has been get the dispersion characteristics and coupling impedance curve. Comparative experimental measurements and simulation of the measured dispersion curve, the simulation found closer to working condition. Giving the influence of dispersion characteristic curve and the coupling impedance by change the key parameters of Hughes-type coupled cavity TWT slow-wave structure. Provide a certain reference value to improve the level of actual traveling wave tube products.