Thermal Analysis and Experiment of a Ka-Band High-Power Output Window

In this paper, an output window designed for sheet beam travelling wave tube (SB-TWT) with special structure and material is analyzed. The window has a wide bandwidth in Ka-band and simulations show that the reflection coefficient is better than -20 dB within the bandwidth of ~9 GHz (26.2 GHz – 35.2 GHz). The window is designed to operate in continuous wave (CW) state and the power capacity is greater than 12 kW. The output window and the water-cooling system works steadily with 4 kW CW output power at experiment.