[3] [3] CAI Jun,FENG Jinjun,WU Xianping. Folded waveguide slow wave structure with modified circular bends[J]. IEEE Transactions on Electron Devices, 2014,61(10):3534-3538. doi:10.1109/TED.2014.2349651.

[6] [6] THEISS A J, MEADOWS C J, FREEMAN R, et al. High-average-power W-band TWT development[J]. IEEE Transactions on Plasma Science, 2010,38(6):1239-1243. doi: 10.1109/TPS.2010.2041794.

[7] [7] COOK A M,WRIGHT E L,NGUYEN K T,et al. Demonstration of a W-band-Traveling-Wave Tube power amplifier with 10 GHz bandwidth[J]. IEEE Transaction on Electron Devices, 2021,68(5):2492-2498. doi:10.1109/TED.2021.3068926.

[8] [8] DU Yinghua, CAI Jun, PAN Pan, et al. Experimental investigation of an ultra-wide-bandwidth W-band pulsed Traveling Wave Tube with microfabricated Folded Waveguide circuits[J]. IEEE Transaction on Plasma Science, 2019, 47(1): 219-225. doi:10.1109/TPS.2018.2880792.