G-Band Wide-Bandwidth Traveling-Wave Tube Based on Sine Waveguide

A G-band phase-velocity-taper Sine waveguide traveling wave tube (TWT) with circular electron beam is proposed to amplify terahertz millimeter waves, based on the characteristics of a sine waveguide with wide bandwidth and low loss. In the design work, the high frequency system of the traveling wave tube was first designed, including the slow wave structure, the input/output coupler, connectors and the attenuator. Finally, the injected wave interaction model is calculated. The results show that the tube with phase taper structure can produce over 21W output power and 33dB gain at typical frequency 220GHz with an operating voltage of 17.2 kV, a current of 0.035A, and an input power of 10mW. In the range of 214GHz to 226GHz, the output power is more than 14W and the gain is more than 28dB.