Design of Output Window for 0.5THz Backward Wave Oscillator

We reported the design of output window for 0.5THz backward wave oscillator. The initial parameters were determined by equivalent theories, then simulated and optimized by CST microwave studio. In this paper, sapphire was selected as the window material, and we obtained a pillbox output window with the voltage standing wave ratio of less than 1.1 in the frequency range of 0.502~0.519THz. The influences of structural parameter changes on the output performance were analyzed.