Influence of load mismatch on output characteristics of klystron

The influence of load mismatch on resonant frequency, gap impedance and external Q factor of klystron output circuit has been studied by using microwave equivalent circuit and 3D electromagnetic software. And the influence of load mismatch on the efficiency of klystron was calculated by 1D large signal klystron code. The calculation results of C band klystron indicate that for single-gap output cavity, the change of resonant frequency caused by load mismatch is smaller and the changes of gap impedance and equivalent external Q factor are bigger. When the voltage standing wave ratio(VSWR) of load is 1.5, the resonant frequency changes about 35 MHz, the real part of gap impedance varies from 3 660 Ω to 7 998 Ω, the external Q factor varies from 36.9 to 93.5, and the efficiency at central f