340 GHz倒圆角交错双栅行波管的仿真与冷测（英文）
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摘要
近些年来交错双栅行波管由于其高功率容量和易加工等优点受到了很多的关注.然而随着器件工作频率的升高,尤其对于太赫兹频段,结构的损耗严重限制了行波管的性能.本文考虑了损耗和加工所导致的圆角等因素,针对交错双栅结构提出了一个更切实际的设计.仿真结果表明,该行波管在320～342 GHz频率范围内能获得大于5 W的输出功率.采用了相速跳变方法来提高输出功率,在整个工作频带内输出功率都得到了大于28%的提升.在此基础上加工了340 GHz交错双栅慢波结构并开展了冷测实验,在330～360 GHz范围内盒型窗的S21测试结果大于-2. 1 d B且电压驻波比在334～355 GHz范围内小于1. 35.同时对包含盒型窗部件的高频系统进行了冷测,其电压驻波比测试结果在335～344 GHz范围内均小于2,且该冷测结果与仿真结果之间趋势基本一致.
Staggered double vane traveling wave tubes have been given a lot of attentions in recent years due to its high power capacity and easy fabrication. However,the loss seriously limits the performance of traveling wave tube with the increasing of frequency,especially in THz wave band. In this paper,a more practical design about staggered double vane structure is proposed with the consideration of the loss and fillets caused by fabrication. The simulation results indicate that the tube with uniform period slow wave structures can obtain over 5 W output power in the frequency range from 320 GHz to 342 GHz. The method of phase-velocity taper is used to enhance the output power and the simulation results show an obvious improvement of the power with more than 28% in the operating wave band. Based on these,the experiment of the fabricated high frequency system with filleted staggered double vane slow wave structure is carried out. The tested S21 of pillbox window is above-2. 1 dB in the frequency range from 330 GHz to 360 GHz and VSWR( voltage standing wave ratio) is below 1. 35 in the frequency range from~334 GHz to 355 GHz. And the tested VSWR of the high frequency system including the pillbox window is below 2 in the frequency range from 335 GHz to 344 GHz,which matches with the simulation results.
Staggered double vane traveling wave tubes have been given a lot of attentions in recent years due to its high power capacity and easy fabrication. However,the loss seriously limits the performance of traveling wave tube with the increasing of frequency,especially in THz wave band. In this paper,a more practical design about staggered double vane structure is proposed with the consideration of the loss and fillets caused by fabrication. The simulation results indicate that the tube with uniform period slow wave structures can obtain over 5 W output power in the frequency range from 320 GHz to 342 GHz. The method of phase-velocity taper is used to enhance the output power and the simulation results show an obvious improvement of the power with more than 28% in the operating wave band. Based on these,the experiment of the fabricated high frequency system with filleted staggered double vane slow wave structure is carried out. The tested S21 of pillbox window is above-2. 1 dB in the frequency range from 330 GHz to 360 GHz and VSWR( voltage standing wave ratio) is below 1. 35 in the frequency range from~334 GHz to 355 GHz. And the tested VSWR of the high frequency system including the pillbox window is below 2 in the frequency range from 335 GHz to 344 GHz,which matches with the simulation results.
引文
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[14]Lai J Q,Gong Y B,Xu X,et al. W-band 1 kW staggered doublevane traveling-wave tube[J]. IEEE Transactions on Electron Devices,2012,59(2):496-503.
[15]Palm A,Sirigiri J,Shin Y M. Enhanced traveling wave amplification of co-planar slow wave structure by extended phase-matching[J].Physics of Plasmas,2015,22(9):093121.
[16]Shi X,Billa L R,Gong Y,et al. High efficiency and high power staggered double vane TWT amplifier enhanced by velocity-taper design[J]. Progress in Electromagnetics Research C,2016,66(5):39-46.
[17]Gilmour A S. Principles of traveling-wave tubes[M]. Boston,MA:Artech House,1994.
[18]Hammerstad E,Jensen O. Accurate models for microstrip computer-aided design[C]. 1980 IEEE MTT-S International Microwave symposium Digest,1980:407-409.
[19]Yang B B,Kirley M P,Booske J H. Theoretical and empirical evaluation of surface roughness effects on conductivity in the terahertz regime[J]. IEEE Transactions on Terahertz Science and Technology,2014,4(3):368-375.
[20]CST PS Tutorials,CST Corp.,Houston,TX,USA,2009.[Online]. Available:http://www. cst-china. cn/CST2009/product/
[2]Kleine-Ostmann T,Jastrow C,Baaske K,et al. Field exposure and dosimetry in the THz frequency range[J]. IEEE Transactions on Terahertz Science and Technology,2014,4(1):12-25.
[3]Booske J H,Dobbs R J,Joye C D,et al. Vacuum electronic high power terahertz sources[J]. IEEE Transactions on Terahertz Science and Technology,2011,1(1):54-75.
[4]Sumathy M,Vinoy K J,Datta S K. Analysis of ridge-loaded foldedwaveguide slow-wave structures for broadband traveling-wave tubes[J]. IEEE Transactions on Electron Devices,2010,57(6):1440-1446.
[5]Liang H T,Ruan C J,Xue Q Z,et al. An extended theoretical method used for design of sheet beam electron gun[J]. IEEE Transactions on Electron Devices,2016,63(11):4484-4492.
[6]Booske J H,Kumbasar A H,and Basten M A. Periodic focusing and ponderomotive stabilization of sheet electron beams[J]. Physical Review Letters,1993,71(24):3979-3982.
[7]Kyhl R L,Webster H F. Breakup of hollow cylindrical electron beams[J]. IRE Transactions on Electron Devices,1956,3(4):172-183.
[8]Shi X,Wang Z,Tang T,et al. Theoretical and experimental research on a novel small tunable PCM system in staggered double vane TWT[J]. IEEE Transactions on Electron Devices,2015,62(12):4258-4264.
[9]Shin Y M and Barnett L R. Intense wideband terahertz amplification using phase shifted periodic electron-plasmon coupling[J]. Applied Physics Letters,2008,92(9):091501.
[10]Shin Y M,Baig A,Barnett L R,et al. System design analysis of a0. 22 THz sheet-beam traveling-wave tube amplifier[J]. IEEE Transactions on Electron Devices,2012,59(1):234-240.
[11]Shin Y M,Barnett L R,and Luhmann N C. Strongly confined plasmonic wave propagation through an ultrawideband staggered double grating waveguide[J]. Applied Physics Letters,2008,93(22):221504.
[12]Shin Y M,Barnett L R,Luhmann N C. Phase-shifted traveling-wavetube circuit for ultrawideband high-power submillimeter-wave generation[J]. IEEE Transactions on Electron Devices,2009,56(5):706-712.
[13]Shin Y M,Zhao J F,Barnett L R,et al. Investigation of terahertz sheet beam traveling wave tube amplifier with nanocomposite cathode[J]. Physics of Plasmas,2010,17(12):123105.
[14]Lai J Q,Gong Y B,Xu X,et al. W-band 1 kW staggered doublevane traveling-wave tube[J]. IEEE Transactions on Electron Devices,2012,59(2):496-503.
[15]Palm A,Sirigiri J,Shin Y M. Enhanced traveling wave amplification of co-planar slow wave structure by extended phase-matching[J].Physics of Plasmas,2015,22(9):093121.
[16]Shi X,Billa L R,Gong Y,et al. High efficiency and high power staggered double vane TWT amplifier enhanced by velocity-taper design[J]. Progress in Electromagnetics Research C,2016,66(5):39-46.
[17]Gilmour A S. Principles of traveling-wave tubes[M]. Boston,MA:Artech House,1994.
[18]Hammerstad E,Jensen O. Accurate models for microstrip computer-aided design[C]. 1980 IEEE MTT-S International Microwave symposium Digest,1980:407-409.
[19]Yang B B,Kirley M P,Booske J H. Theoretical and empirical evaluation of surface roughness effects on conductivity in the terahertz regime[J]. IEEE Transactions on Terahertz Science and Technology,2014,4(3):368-375.
[20]CST PS Tutorials,CST Corp.,Houston,TX,USA,2009.[Online]. Available:http://www. cst-china. cn/CST2009/product/