The bandwidth of the high power klystron strongly depends on its output power level. Usually, the relative bandwidth is about 1~2% for X-band CW klystron with output power of several kilowatts. The relative bandwidth of 3~4% is required for some application for 5kW X-band CW klystron. In this paper, the design and calculation of the X-band klystron are presented. By optimizing the parameters of electron beam and RF interaction section, the relative bandwidth of 4%, efficiency of 25%, gain of 25dB have been obtained for 5kW X band CW klystron at beam voltage of 14kV and beam current of 1.66A. The influence of beam filling factor and radius of beam channel on the efficiency-frequency characteristics are described and discussed.

At present the impact of flow regime on heat distribution and cooling capacity of collectors is not considered in the thermal analysis of the liquid-cooled collectors. The liquid-solid coupled heat transfer simulation method for the collectors of high power klystrons is presented. Using the CFX software in the platform of ANSYS Workbench, the model of the collector with two-layer water jacket and ditch grooves is simplified and established. The velocity distribution, the temperature rise, the pressure distribution of the flow and the temperature distribution on the collector are simulated. The results are contrasted with the theoretical results and the errors are reasonable. These simulation results are meaningful to the microwave high power test of klystrons and the optimal design of collectors.

This paper reports a numerical simulation for collector of klystron fluid flow and coupled heat transfer. The structure of collector using in the klystron was simplified. A numerical model of the collector was established by using ANSYS Workbench. Fluid velocity distribution, temperature rise and pressure drop condition inside the collector were obtained and analyzed. This research could be beneficial to the optimal design of cooling system in the klystron and other vacuum electron devices.