Output structure of T-bar transition for A 1 MW CW 650MHz klystron

A 1MW CW 650MHz high efficiency klystron is being designed for the coupled cavity drift tube stage of the Circular Electron Positron Collider (CEPC) in China. As an important part of the klystron, the high power microwave window could keep the vacuum and make the microwave transmit with high efficiency. In this paper, a special kind of coaxial window working in 650MHz have been designed to get a better transmission performance of the P-band klystron output system. The window is matched using the coax to waveguide T-bar transition. The preliminary design study of the RF window is presented.