Development of a broadband output circuit for a Ku-band Extended Interaction Klystron

A broadband output circuit for a 50kW Ku-band Extended Interaction Klystron is developed in the Institute of Electronics, Chinese Academy of Sciences (IECAS) recently. The design, calculation and result of cold test of the output circuit are presented in the paper. The output circuit employs a filter loaded double-gap coupling cavity out section with mode coalescence. In result, a 450MHz bandwidth of the output circuit is got while the impedance R11+R22>;4400Ω.