Thermal analysis of a output window for 108GHz folded waveguide traveling-wave tube

A sapphire output window is designed for 108GHz folded waveguide traveling-wave tube (FW-TWT). The voltage standing wave ratio (VSWR) is calculated using CST Microwave Studio (MWS). The transmission modes in the window are analyzed. Thermal analysis of the output window using ANSYS package is presented. With different power losses in the window, temperature, total deformation and equivalent stress had been simulated considering different transmission modes in the window. The results show that all aspects of the designed output window can meet the requirement of thermodynamics.