[3] [3] PAOLONI Claudio,LETIZIA Rosa,ZIMMERMAN Ralph,et al. W-band TWTs for new generation high capacity wireless networks[C]// IEEE International Vacuum Electronics Conference(IVEC). Monterey,CA,USA:IEEE, 2016:521-522.

[4] [4] PALMER W D. THz Vacuum Electronics[C]// IEEE International Vacuum Electronics Conference. Monterey, CA, USA: IEEE, 2012:17-18. doi:10.1109/IVEC.2012.6262056.

[6] [6] KOWALCZYK Richard,ZUBYK Andrew,MEADOWS Clark,et al. High efficiency E-band MPM for communication applications[C]// International Vacuum Electronics Conference. Monterey,CA,USA:IEEE, 2016:513-514. doi:10.1109/IVEC.2016.7561861.

[7] [7] XIE Qingmei, LIU Shishuo, CHEN Zhaofei, et al. A 81-86 GHz TWTA for wireless communication[C]// International Vacuum Electronics Conference. Rotterdam,Netherlands:IEEE, 2021:1-2. doi:10.1109/IVEC51707.2021.9722549.

[9] [9] LIU Shishuo,XIE Qingmei,CHEN Zhaofei,et al. High linear power E-Band traveling-wave tube for communication applications[J]. IEEE Transactions on Electron Devices, 2021,68(5):2984-2989. doi:10.1109/TED.2021.3073382.

[10] [10] THEISS Alan J, MEADOWS Clark J, FREEMAN Ray, 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.

[11] [11] COOK Alan M,WRIGHT Edward L,NGUYEN Khanh T,et al. Demonstration of a W-band traveling-wave tube power amplifier with 10 GHz bandwidth[J]. IEEE Transactions on Electron Devices, 2021,68(5):2492-2498. doi:10.1109/TED.2021.3068926.

[12] [12] CHEN Ji,WANG Zhigang,WANG Fengyan,et al. Demonstration of a broadband W-band microwave power module with improved gain flatness[J]. IEEE Electron Device Letters, 2022,43(8):1335-1338. doi:10.1109/LED.2022.3185157.

[13] [13] DU Yinghua,CAI Jun,ZHANG Xiaoqing,et al. A substantially lowered-voltage high-power W-band pulsed traveling wave tube[J]. IEEE Microwave and Wireless Components Letters, 2021,31(6):590-592. doi:10.1109/LMWC.2021.3070637.

[14] [14] ZHANG Xiaoqing, FENG Jinjun, CAI Jun, et al. Power enhancement in W-band pulsed folded waveguide TWT[J]. IEEE Transactions on Electron Devices, 2021,68(5):2504-2508. doi:10.1109/TED.2021.3068692.

[15] [15] ZHANG Xiaoqing,FENG Jinjun,CAI Jun,et al. High-efficiency W-band pulsed TWT with three-stage depressed collector[J]. IEEE Microwave and Wireless Components Letters, 2022,32(2):121-124. doi:10.1109/LMWC.2021.3122124.

[16] [16] JOYE C D, COOK A M, CALAME J P, et al. Wideband 220 GHz traveling wave amplifier fabricated by UV-LIGA[J]. IEEE Transactions on Electron Devices, 2014,61(6):1672-1678. doi:10.1109/TED.2014.2300014.

[17] [17] BASTEN M A, TUCEK J C, GALLAGHER D A, et al. 233 GHz high power amplifier development at Northrop Grumman[C]// IEEE International Vacuum Electronics Conference(IVEC). Monterey,CA,USA:IEEE, 2016:43-44. doi:10.1109/IVEC.2016.7561775.

[18] [18] ARMSTRONG C M, KOWALCZYK R, ZUBYK A, et al. A compact extremely high frequency MPM power amplifier[J]. IEEE Transactions on Electron Devices, 2018,65(6):2183-2188. doi:10.1109/TED.2018.2808327.

[19] [19] PAN Pan,TANG Ye,BIAN Xingwang,et al. A G-band traveling wave tube with 20 W continuous wave output power[J]. IEEE Electron Device Letters, 2020,41(12):1833-1836. doi:10.1109/LED.2020.3032562.

[20] [20] BIAN Xingwang, PAN Pan, TANG Ye, et al. Demonstration of a pulsed G-band 50 W traveling wave tube[J]. IEEE Electron Device Letters, 2021,42(2):248-251. doi:10.1109/LED.2020.3044450.

[21] [21] FENG Yuan, BIAN Xingwang, SONG Bowen, et al. A G-band broadband continuous wave traveling wave tube for wireless communications[J]. Micromachines, 2022,13(10):1635. doi:10.3390/mi13101635.

[22] [22] PAN Pan,ZHANG Lin,CUI Hengshan,et al. Terahertz power module based on 0.34 THz traveling wave tube[J]. IEEE Electron Device Letters, 2022,43(5):816-819. doi:10.1109/LED.2022.3164660.

[23] [23] HU Peng, LEI Wenqiang, JIANG Yi, et al. The vacuum window for 0.34 THz folded waveguide traveling wave tube[J]. IEEE Electron Device Letters, 2019,40(6):973-976. doi:10.1109/IVEC.2019.8744802.

[24] [24] TUCEK Jack C,BASTEN Mark A,GALLAGHER David A,et al. A 100 mW, 0.670 THz power module[C]// IEEE International Vacuum Electronics Conference. Monterey,CA,USA, 2012:31-32. doi:10.1109/IVEC.2012.6262062.

[25] [25] TUCEK Jack C, BASTEN Mark A, GALLAGHER David A, et al. 0.850 THz vacuum electronic power amplifier[C]// IEEE International Vacuum Electronics Conference. Monterey,CA,USA:IEEE, 2014:153-154. doi:10.1109/IVEC.2014.6857535.

[26] [26] TUCEK Jack C, BASTEN Mark A, GALLAGHER David A, et al. Operation of a compact 1.03 THz power amplifier[C]// IEEE International Vacuum Electronics Conference. Monterey,CA,USA:IEEE, 2016:37-38. doi:10.1109/IVEC.2016.7561772.

[27] [27] 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.

[30] [30] ZHANG Xiaoqing, FENG Jinjun, CAI Jun, et al. Design and experimental study of 250 W W-band pulsed TWT with 8 GHz bandwidth[J]. IEEE Transactions on Electron Devices, 2017,64(12):5151-5156. doi:10.1109/TED.2017.2766664.

[31] [31] LIU Shishuo,XIE Qingmei,CHEN Zhaofei,et al. High linear power E-band traveling-wave tube for communication applications[J]. IEEE Transaction on Electron Devices, 2021,68(6):2984-2989. doi:10.1109/TED.2021.3073382.

[32] [32] ZHANG Changqing,FENG Jinjun,CAI Jun,et al. Focusing of the electron beam with two-plane periodic cusped magnetic system for terahertz TWTs[J]. IEEE Transactions on Electron Devices, 2021,68(6):3056-3062. doi:10.1109/TED.2021.3075649.

[33] [33] JI Huanli,YANG Jinsheng,CHEN Ji,et al. Design of an electron gun and PPM focusing system for low-voltage W-band TWTs[C]// IEEE International Vacuum Electronics Conference. Monterey,CA,USA:IEEE, 2022:158-159.