Design of V-band coaxial transit time oscillator with TM03 mode
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摘要: 随着高功率微波源频率的提升,腔体尺寸会随着电磁波波长的缩短而减小,从而导致器件功率容量不足,增大了射频击穿、脉冲缩短的风险。为了提升高频器件的功率容量,提出了一种基于TM03模式的低表面场强V波段同轴渡越时间振荡器,通过引入TM03模式的方式在极高频下拓宽腔体的横向尺寸,从而降低表面场强,提升功率容量。为了激励TM03模式并使之成为器件主要工作模式,计算了束波互作用结构的色散曲线及耦合阻抗,通过腔体设计使TM03模式的相速度与电子速度同步并发生换能,从而获得较低的群速度以及较高的耦合阻抗,最终成功在慢波结构中建立起了TM03模式电磁场。随后的粒子模拟仿真表明,在二极管电压400 kV、电流5 kA的条件下,输出微波功率达440 MW,频率为62.25 GHz,转换效率为22%,最大表面场强为1.6 MV/cm。Abstract: Increasing frequency is always an important development direction of high power microwave (HPM). However, as the frequency increases, the volume of an HPM device decreases rapidly and so does the power handling capacity (PHC). For obtaining reasonable PHC, the design of a V-band coaxial transit time oscillator (TTO) based on TM03 mode is carried out to achieve low surface field in this paper. The slow wave structure (SWS) having a large radial width with TM03 mode in such a device designed will lead to low risk of both electric field breakdown and pulse shortening. Firstly, the synchronous effect of velocity between microwave and electron beam is achieved by calculation of dispersion curve and coupling impedance. Then, small group velocity and high coupling impedance are designed to make TM03 a dominant mode in the coaxial V-band TTO. Finally, under the condition of 440 kV and 5 kA, an HPM is generated to reach an output power of 440 MW with a low surface electric field of 1.6 MV/cm, a microwave frequency of 62.25 GHz, and a beam-to-wave efficiency of 22% from numerical simulation.
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Key words:
- power handling capacity /
- TM03 mode /
- V-band /
- transit time oscillator /
- low surface electric field
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表 1 多周期慢波结构几何结构参数
Table 1. Parameters of slow wave structure
(unit: mm) Rout w dt h N Rin(TM01) Rin(TM02) Rin(TM03) 30.0 1.6 1.4 3.7 14 27.6 24.4 22.9 表 2 轴向表面场强大小
Table 2. Axial surface electric field of TM modes
mode electric field/(V·m−1) TM01 0.41 TM02 0.27 TM03 0.19 -
[1] Benford J, Swegle J A, Schamiloglu E. High power microwaves[M]. 2nd ed. Boca Raton: CRC Press, 2007. [2] Zhang Jiande, Ge Xingjun, Zhang Jun, et al. Research progresses on Cherenkov and transit-time high-power microwave sources at NUDT[J]. Matter and Radiation at Extremes, 2016, 1(3): 163-178. doi: 10.1016/j.mre.2016.04.001 [3] 贺军涛. 新型渡越时间振荡器的研究[D]. 长沙: 国防科技大学, 2004He Juntao. Investigation on novel transit-time oscillators[D]. Changsha: National University of Defense Technology, 2004 [4] 曹亦兵. 基于渡越辐射新型高功率微波源的研究[D]. 长沙: 国防科技大学, 2012Cao Yibing. Investigation of a novel high-power microwave source based on transition radiation effect[D]. Changsha: National University of Defense Technology, 2012 [5] 令钧溥. Ku波段低磁场同轴渡越时间振荡器的研究[D]. 长沙: 国防科技大学, 2014Ling Junpu. Investigation of a Ku-band coaxial transit-time oscillator with low guiding magnetic field[D]. Changsha: National University of Defense Technology, 2014 [6] 宋莉莉. Ka波段高功率同轴渡越时间振荡器的研究[D]. 长沙: 国防科技大学, 2018Song Lili. A Ka-band high power coaxial transit-time oscillator[D]. Changsha: National University of Defense Technology, 2018 [7] 周传明, 刘国治, 刘永贵, 等. 高功率微波源[M]. 北京: 原子能出版社, 2007Zhou Chuanming, Liu Guozhi, Liu Yonggui, et al. High-power microwave sources[M]. Beijing: Atomic Energy Press, 2007 [8] Benford J, Swegle J A, Schamiloglu E. 高功率微波[M]. 江伟华, 张驰, 译. 2版. 北京: 国防工业出版社, 2009Benford J, Swegle J A, Schamiloglu E. High power microwaves[M]. Jiang Weihua, Zhang Chi, trans. 2nd ed. Beijing: National Defense Industry Press, 2009 [9] Miller R B. 强流带电粒子束物理学导论[M]. 刘锡三, 张兰芝, 吴衍斌, 等译. 北京: 原子能出版社, 1990Miller R B. Intense electron beam physics[M]. Liu Xisan, Zhang Lanzhi, Wu Yanbin, et al, trans. Beijing: Atomic Energy Press, 1990 [10] 白珍. Ka波段大过模同轴Cerenkov型高功率微波振荡器研究[D]. 长沙: 国防科技大学, 2017Bai Zhen. Investigation on Ka-band super overmoded coaxial Cerenkov high power microwave oscillator[D]. Changsha: National University of Defense Technology, 2017 [11] Vlasov A N, Shkvarunets A G, Rodgers J C, et al. Overmoded GW-class surface-wave microwave oscillator[J]. IEEE Transactions on Plasma Science, 2000, 28(3): 550-560. doi: 10.1109/27.887671 [12] 张点. 过模O型Cerenkov高功率微波产生器件相关理论和关键问题研究[D]. 长沙: 国防科技大学, 2014Zhang Dian. Investigation on related theory and key problems of overmoded O-type Cerenkov high power microwave generators[D]. Changsha: National University of Defense Technology, 2014 [13] Deng Bingfang, He Juntao, Ling Junpu, et al. Theoretical analysis and experimental verification of electron beam transmission with low guiding magnetic field in V-band coaxial transit-time oscillator[J]. Physics of Plasmas, 2021, 28: 073102. doi: 10.1063/5.0042738 [14] Ye Hu, Teng Yan, Chen Changhua, et al. A millimeter wave relativistic backward wave oscillator operating in TM03 mode with low guiding magnetic field[J]. Physics of Plasmas, 2015, 22: 063104. doi: 10.1063/1.4922428 [15] Deng Bingfang, He Juntao, Ling Junpu. A coaxial V-band relativistic transit-time oscillator operating in TM02 mode[J]. IEEE Transactions on Plasma Science, 2020, 48(12): 4350-4355. doi: 10.1109/TPS.2020.3039051 [16] Deng Bingfang, He Juntao, Ling Junpu, et al. Preliminary research of a V-band coaxial relativistic transit-time oscillator with traveling wave output structure[J]. Physics of Plasmas, 2021, 28: 103103. doi: 10.1063/5.0060186 [17] Ye Hu, Chen Changhua, Ning Hui, et al. Preliminary research on overmoded high-power millimeter-wave Cerenkov generator with dual-cavity reflector in low guiding magnetic field[J]. Physics of Plasmas, 2015, 22: 123110. doi: 10.1063/1.4937777 [18] Deng Bingfang, He Juntao, Ling Junpu, et al. A V-band coaxial relativistic transit-time oscillator operating in TM02 mode with shallow corrugated output structure[J]. IEEE Electron Device Letters, 2022, 43(7): 1125-1128. doi: 10.1109/LED.2022.3178071 [19] Amin M R, Ogura K, Kitamura H, et al. Analysis of the electromagnetic waves in an overmoded finite length slow wave structure[J]. IEEE Transactions on Microwave Theory and Techniques, 1995, 43(4): 815-822. doi: 10.1109/22.375229 [20] Miller S M, Antonsen Jr T M, Levush B, et al. Theory of relativistic backward wave oscillators operating near cutoff[J]. Physics of Plasmas, 1994, 1(3): 730-740. doi: 10.1063/1.870818