Design of power combiner for X-band high power klystron

With the urgent need of high power sources, a design method for power combiner of X-band high power klystron based on microwave theory and EBMA(extended boundary condition modal analysis) is presented in this paper. Power combiner can combine the input from its rectangular arms into one central circular waveguide working in TE01 mode, so the transmission parameter can determine its performance. Using EBMA and CST software, the transmission parameter of the designed 4-to-1 power combiner is calculated as 1 and 0.99, respectively, which can confirm its validity. For 8-to-1 power combiner, a simplified model has been proposed, which makes possible the calculation of gap impedance of an output cavity after its loading.