Analysis of 140 gigahertz folded frame travelling wave tube

A study on the low voltage, high efficiency and wide bandwidth travelling wave tube by using a novel folded frame slow-wave structure is carried out in this paper. The radio frequency characteristics of the folded frame structure, including dispersion property, interaction impedances, and reflection property are investigated and compared to the similar symmetric double V-shape meander-line structure. Then, the beam-wave interaction process of the folded frame travelling wave tube (TWT) with rectangular sheet electron beam is simulated by 3-D particle-in-cell algorithms. The results show that the output power and electron efficiency can reach 259 W and 13.5% at the center frequency of 140 GHz, respectively. Simultaneously, the instantaneous 3-dB bandwidth is 24 GHz. Compared to the symmetric double V-shaped TWT, the output power and electron efficiency of the folded frame TWT are increased