Slow-wave circuits and power synthesis techniques of folded waveguides for terahertz applications
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摘要: 针对太赫兹频段行波管输出功率较小的瓶颈以及对紧凑型设计的明确需求,提出一种管内功率合成的0.34 THz折叠波导行波管结构。首先,对太赫兹折叠波导慢波结构的高频特性进行了研究,通过仿真计算得到了其色散特性和耦合阻抗,0.34 THz处归一化相速度为0.248,耦合阻抗为0.46 Ω;其次,提出了用于管内功率合成的3 dB定向耦合器结构设计,分析表明,其在0.31~0.368 THz范围内,幅度平衡度在±0.19 dB以内,隔离度优于24 dB;最后,完成了基于3 dB定向耦合器管内功率合成的折叠波导行波管基本结构设计并构建了仿真模型,仿真结果表明,最大输出功率为9.16 W,增益为26.6 dB,3 dB带宽达到21 GHz。作为对比,单个折叠波导行波管输出功率为6.18 W,故管内合成的折叠波导行波管的输出功率是单个行波管输出功率的1.48倍;此外,与采用常规外置功率合成结构的双行波管组件设计相比,管内功率合成折叠波导行波管的横向尺寸至少缩减了56.5%。Abstract: Aiming to address the bottleneck of low output power in terahertz band traveling wave tubes and responding to the distinct demand for compact design, this paper proposes a 0.34 THz folded waveguide traveling wave tube structure with power combination inside the tube. Firstly, the high-frequency characteristics of the folded waveguide slow-wave structure are investigated. Electromagnetic full-wave simulations are used to obtain its dispersion characteristics and coupling impedance. The normalized phase velocity at 0.34 THz is 0.248 and the coupling impedance is 0.46 Ω. Secondly, a 3 dB directional coupler structure for in-tube power combination is designed. The analysis indicates that its amplitude balance is within ±0.19 dB in the range of 0.31–0.368 THz, and the isolation exceeds 24 dB. Finally, the basic structure of the folded waveguide traveling wave tube based on the in-tube combination of the 3 dB directional coupler is demonstrated. The simulation model is constructed, and the results show a maximum output power of 9.16 W, a gain of 26.6 dB, and a 3 dB bandwidth of 21 GHz. For comparison, the output power of a single folded waveguide traveling wave tube is 6.18 W. The output power of the in-tube synthesized folded waveguide traveling wave tube is 1.48 times that of the single traveling wave tube. Moreover, compared with the design of a dual-tube assembly using conventional external power combination structure, the lateral size is reduced by at least 56.5%.
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表 1 慢波结构参数
Table 1. Structure parameters of slow wave structure
unit: mm a b p h r 0.56 0.12 0.18 0.20 0.08 -
[1] 蔡军, 冯进军. 太赫兹行波管及其通信应用进展[J]. 真空电子技术, 2021, 34(3):10-18,40Cai Jun, Feng Jinjun. THz TWT and its application progress in communication[J]. Vacuum Electronics, 2021, 34(3): 10-18,40 [2] 赵国忠. 太赫兹科学技术研究的新进展[J]. 国外电子测量技术, 2014, 33(2):1-6,20 doi: 10.3969/j.issn.1002-8978.2014.02.001Zhao Guozhong. Progress on terahertz science and technology[J]. Foreign Electronic Measurement Technology, 2014, 33(2): 1-6,20 doi: 10.3969/j.issn.1002-8978.2014.02.001 [3] 刘盛纲, 钟任斌. 太赫兹科学技术及其应用的新发展[J]. 电子科技大学学报, 2009, 38(5):481-486 doi: 10.3969/j.issn.1001-0548.2009.05.001Liu Shenggang, Zhong Renbin. Recent development of terahertz science and technology and it's applications[J]. Journal of University of Electronic Science and Technology of China, 2009, 38(5): 481-486 doi: 10.3969/j.issn.1001-0548.2009.05.001 [4] 陈科, 张合泰, 徐倩, 等. 300GHz折叠波导行波管高频结构的设计与测试[J]. 真空电子技术, 2019, 32(2):19-23Chen Ke, Zhang Hetai, Xu Qian, et al. Design and cold test of the high frequency system for a 300GHz folded-waveguide traveling wave tube[J]. Vacuum Electronics, 2019, 32(2): 19-23 [5] 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 [6] 徐翱, 周泉丰, 阎磊, 等. 0.34THz折叠波导行波管设计[C]//中国电子学会真空电子学分会第十九届学术年会论文集(上册). 2013: 3Xu Ao, Zhou Quanfeng, Yan Lei, et al. The design of a 0.34THz folded waveguide traveling wave tube[C]//Proceedings of the 19th Annual Conference of the Vacuum Electronics Division of the Chinese Institute of Electronics (Upper Volume). 2013: 3 [7] Li Ke, Liu Wenxin, Wang Yong, et al. Design and simulation of 340GHz folded waveguide traveling wave tube[C]//2015 IEEE International Vacuum Electronics Conference (IVEC). 2015: 1-2. [8] 潘攀, 李含雁, 唐烨, 等. 340GHz行波管设计与试验研究[C]//2016真空电子学分会第二十届学术年会论文集(上). 2016: 5Pan Pan, Li Hanyan, Tang Ye, et al. 340 GHz travelling wave tube design and experimental study[C]//Proceedings of the Twentieth Annual Conference of the Vacuum Electronics Division 2016 (Top). 2016: 5 [9] Zhang Lin, Pan Pan, Jia Meng, et al. Demonstration of 0.34THz traveling wave tube amplifier[C]//2023 24th International Vacuum Electronics Conference (IVEC). 2023: 1-2. [10] 颜胜美, 苏伟, 王亚军, 等. 双注THz折叠波导行波管的设计与传输特性实验[J]. 太赫兹科学与电子信息学报, 2015, 13(1):13-18 doi: 10.11805/TKYDA201501.0013Yan Shengmei, Su Wei, Wang Yajun, et al. Design and transmission test of two-beam terahertz folded waveguide traveling wave tubes[J]. Journal of Terahertz Science and Electronic Information Technology, 2015, 13(1): 13-18 doi: 10.11805/TKYDA201501.0013 [11] 唐烨, 潘攀, 张琳, 等. G波段大功率连续波行波管[J]. 真空电子技术, 2021, 34(3):28-31,50Tang Ye, Pan Pan, Zhang Lin, et al. G-band high power CW TWTs[J]. Vacuum Electronics, 2021, 34(3): 28-31,50 [12] Zheng Ruilin, Ohlckers P, Chen Xuyuan. Particle-in-cell simulation and optimization for a 220-GHz folded-waveguide traveling-wave tube[J]. IEEE Transactions on Electron Devices, 2011, 58(7): 2164-2171. doi: 10.1109/TED.2011.2145420 [13] Bhattacharjee S, Booske J H, Kory C L, et al. Folded waveguide traveling-wave tube sources for terahertz radiation[J]. IEEE Transactions on Plasma Science, 2004, 32(3): 1002-1014. doi: 10.1109/TPS.2004.828886 [14] 张长青. 大功率毫米波折叠波导行波管的研究[D]. 成都: 电子科技大学, 2011Zhang Changqing. Investigation of the high-power millimeter wave folded waveguide traveling-wave tube[D]. Chengdu: University of Electronic Science and Technology of China, 2011 [15] 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 [16] 赵征远, 刘文鑫, 杨龙龙, 等. 0.34THz双注高次模折叠波导行波管高频系统设计[J]. 强激光与粒子束, 2021, 33:053003 doi: 10.11884/HPLPB202133.210002Zhao Zhengyuan, Liu Wenxin, Yang Longlong, et al. Design of high frequency system of 0.34THz high order mode two-beam folded waveguide traveling wave tube[J]. High Power Laser and Particle Beams, 2021, 33: 053003 doi: 10.11884/HPLPB202133.210002 [17] Jin Liang, Li Xiaojun, Zhu Zhongbo. A terahertz 3dB waveguide power divider with 90° phase shifter integrated[J]. Journal of Physics: Conference Series, 2021, 1871: 012056. doi: 10.1088/1742-6596/1871/1/012056 [18] 师娅楠, 张斌珍, 段俊萍, 等. 一种新型太赫兹分支波导定向耦合器设计[J]. 固体电子学研究与进展, 2019, 39(5):339-343Shi Yanan, Zhang Binzhen, Duan Junping, et al. Design of a novel terahertz branch waveguide directional coupler[J]. Research Progress of Solid State Electronics, 2019, 39(5): 339-343 [19] Deng Jiangyu, Duan Junping, Liu Rui, et al. A 3 dB E-plane waveguide directional coupler employing micromachining technique for terahertz application[J]. Microwave and Optical Technology Letters, 2020, 62(11): 3425-3431. doi: 10.1002/mop.32470