翼片加载螺旋线慢波结构特性研究
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摘要
在现代国民经济部门如通讯、雷达、航空航天等，以及现代化军事装备如雷达、干扰机等中，宽带大功率行波管的应用具有举足轻重、无可替代的作用。螺旋线是宽带行波管中一种重要的慢波结构，它具有结构简单、易于制造、良好的色散特性、较高的耦合阻抗等一系列优点。对它的研究有助于改善它的慢波性能，实现行波管的计算机辅助设计(CAD)，提高行波管的总体性能。
本文利用场论求解的方法，采用螺旋导电面模型，将实际的螺旋线看成一个螺旋导电圆筒，圆筒上沿螺旋线前进的方向理想导电，而与其垂直的方向完全不导电，建立了翼片加载螺旋线慢波结构的导电面模型，得到了各区的场表达式。并进一步推导了实用的色散方程、耦合阻抗和衰减常数表达式。
采用螺旋带模型，假设螺旋线由金属带绕成，在圆柱坐标下写出螺旋线内、外两区中场的一般展开式，然后从假定的螺带电流出发求出展开式中的幅值系数。推导出了相应的色散方程、耦合阻抗和衰减常数表达式。
利用导出的方程，采用可视化技术，在Visual C++环境下，开发了螺旋慢波结构高频系统CAD软件：Helix，并成功的应用于行波管CAD集成环境软件包中。对实际行波管用螺旋慢波结构进行计算，并将色散关系、耦合阻抗、衰减常数的测量结果与导电面模型、螺旋带模型的计算结果进行了比较，得出了相同条件下，螺旋带模型优于导电面模型的结论。对螺旋带模型，分析了两种不同电流假设对色散特性的影响，并计算了不同夹持杆介电常数、不同管壳半径对色散特性的影响。
采用行波法对翼片加载螺旋慢波结构的色散特性进行了冷测实验，测试结果验证了理论分析的可靠性。
The broad-band and high power traveling-wave tube(TWT) is very important in the modern military equipments such as Radar > jammer etc. The Helical slow-wave structures find wide application as RF interaction structures in the traveling-wave tubes. It has many advantages such as the simple structure, excellent dispersion characteristic and the high interaction impedance.
First of all, the field theory based on the sheath model is used to study the characteristic of the helix in this dissertation. An actual helix is regarded as the helical conductive cylinder. By means of this model, the utility dispersion equation, the interaction impedance and the attenuation constant are obtained.
Besides, the tape helix model is suggested too. In this model, the fields of the inside and outside helix have been expanded by the space harmonics, and then the expanded coefficient can be sovled from the given tape current utlizing the condition on boundary. Moreover, the dispersion equations, as well as the interaction impedance and the attenuation are worked out.
"Helix", a CAD software on the helical slow-wave structure is developed by the derived equations and the visual technology under Visual C++, and it is used successfully in TWT CAD software packet. Some typical helical slow-wave structures of TWT are calculated by the derived equations. The calculating results on the sheath and tape model are compared with those of the measurements. It is shown that the tape helix model is better than the sheath model under same conditions. The influence on dispersion characteristic is analyzed for two types of hypothesis current, the different permittivity of the dielectric support and the different radius of the metal envelope.
The dispersion characteristic of a vane-loaded helical slow-wave structure is
investigated experimentally by the travelling wave method. The "cold" test results are in good agreement with the theoretical results.
本文利用场论求解的方法，采用螺旋导电面模型，将实际的螺旋线看成一个螺旋导电圆筒，圆筒上沿螺旋线前进的方向理想导电，而与其垂直的方向完全不导电，建立了翼片加载螺旋线慢波结构的导电面模型，得到了各区的场表达式。并进一步推导了实用的色散方程、耦合阻抗和衰减常数表达式。
采用螺旋带模型，假设螺旋线由金属带绕成，在圆柱坐标下写出螺旋线内、外两区中场的一般展开式，然后从假定的螺带电流出发求出展开式中的幅值系数。推导出了相应的色散方程、耦合阻抗和衰减常数表达式。
利用导出的方程，采用可视化技术，在Visual C++环境下，开发了螺旋慢波结构高频系统CAD软件：Helix，并成功的应用于行波管CAD集成环境软件包中。对实际行波管用螺旋慢波结构进行计算，并将色散关系、耦合阻抗、衰减常数的测量结果与导电面模型、螺旋带模型的计算结果进行了比较，得出了相同条件下，螺旋带模型优于导电面模型的结论。对螺旋带模型，分析了两种不同电流假设对色散特性的影响，并计算了不同夹持杆介电常数、不同管壳半径对色散特性的影响。
采用行波法对翼片加载螺旋慢波结构的色散特性进行了冷测实验，测试结果验证了理论分析的可靠性。
The broad-band and high power traveling-wave tube(TWT) is very important in the modern military equipments such as Radar > jammer etc. The Helical slow-wave structures find wide application as RF interaction structures in the traveling-wave tubes. It has many advantages such as the simple structure, excellent dispersion characteristic and the high interaction impedance.
First of all, the field theory based on the sheath model is used to study the characteristic of the helix in this dissertation. An actual helix is regarded as the helical conductive cylinder. By means of this model, the utility dispersion equation, the interaction impedance and the attenuation constant are obtained.
Besides, the tape helix model is suggested too. In this model, the fields of the inside and outside helix have been expanded by the space harmonics, and then the expanded coefficient can be sovled from the given tape current utlizing the condition on boundary. Moreover, the dispersion equations, as well as the interaction impedance and the attenuation are worked out.
"Helix", a CAD software on the helical slow-wave structure is developed by the derived equations and the visual technology under Visual C++, and it is used successfully in TWT CAD software packet. Some typical helical slow-wave structures of TWT are calculated by the derived equations. The calculating results on the sheath and tape model are compared with those of the measurements. It is shown that the tape helix model is better than the sheath model under same conditions. The influence on dispersion characteristic is analyzed for two types of hypothesis current, the different permittivity of the dielectric support and the different radius of the metal envelope.
The dispersion characteristic of a vane-loaded helical slow-wave structure is
investigated experimentally by the travelling wave method. The "cold" test results are in good agreement with the theoretical results.
引文
[1] J.R.Pierce,"Theory of the beam type traveling-wave tube",Proc.I.R.E,35(1947) ,108．
[2] E.F.Belohoubek,"Helix support structure for ultra-wide-band traveling-wave tubes," RCA Rev.,vol.26,pp.106-117,Mar.1965．
[3] R.S.Raju,S.N.Joshi,B.N.Basu,"Modeling of Practical Multi-Octave-Band Helical Slow-Wave Structure of a Traveling-Wave Tube for Interaction Impedance",IEEE Trans.Electron Devices,Vol.39,pp.996-1001,No.4,Apr.1992．
[4] S.Sensiper,"Electromagnetic wave propagation on helical structures",Proc.I.R.E,43(1955) ,149-161．
[5] P.K.Tien,"Traveling-Wave Tube Helix Impedance",Proc.I.R.E,pp.1617-1623,Nov.1953．
[6] S.Ghosh,P.K.Jain,and B.N.Basu,"Rigorous tape analysis of inhomogeneously-loaded helical slow-wave structures",IEEE Trans.Electron Devices,vol.44,ppl 158-1168,1997．
[7] S.D'Agostino,F.Emma,and C.Paoloni,"Accurate Analysis of Helix Slow-Wave Structure" IEEE Trans.Electron Devices,vol.45,pp.1605-1613,No.7 ,Jul 1998．
[8] D.Chernin,T.M.Antonsen,and B.Levush,"Extract Treatment of the Dispersion and Beam Interaction Impedance of a Thin Tape Helix Surrounded by a Radially Stratified Dielectric",IEEE Trans.Electron Devices,vol.46,pp1472-1483,No.7,Jul 1999．
[9] 王自成，陈庆有，吴鸿适，“带状螺旋慢波结构色散的研究”，电子学报， vol.27,No3,pp40-44,1999．
[10] H.P.Freund,"Three-Dimensional Nonlinear Theory of Helix Traveling-Wave Tubes",IEEE Trans.Plasma Science,vol.28,pp.748-759,No.3,Jun 2000．
[11] S.F.Paik,"Design formulas for helix dispersion shaping",IEEE Trans.Electron Devices,vol.16,pp.1010-1014． Dec.1969．
[12] N.P.Kravchenko, L.N.Loshakov, and Y.N.Pchel'nikov, "Computation of Dispersion
Characteristics of a Spiral Placed in a Screen with Longitudinal Ribs", Radio Eng.Electron.Phys.,vol21,pt.1,pp.33-39,Apr.1976．
[13] L.Kumar,R.S.Raju,S.N.Joshi,and B.N.Basu,"Modeling of aVane-Loaded Helical Slow-Wave Structure for Broad-Band Traveling-Wave Tubes",IEEE Trans.Electron Devices,vol.36,pp1991-1999,No.9,Sept 1989．
[14] C.L.Kory,J.A.Dayton,"Computational Investigation of Experimental Interaction Impedance Obtained by Perturbation for Helical Travel ing-Wave Tube Structures",IEEE Trans.Electron Devices,vol.45,pp.2063-2071,No.9,Sept 1998．
[15] S.F.Paik,"Design formulas for helix dispersion shaping ",IEEE Trans.Electron Devices,vol.l6,ppl010-1014,1969．
[16] A.S.Gilmour,M.R.Gillette,Jenn-Tsung Chen,"Theoretical and experimental TWT helix loss determination",IEEE Trans.Electron Devices,vol.10,pp1581-1588,1979．
[17] B.N.Basu,B.B.Pal,V.N.Singh.and N.C.Vaidya,"Optimum design of a potentially dispersion-free helical slow-wave circuit of a broadband TWT",IEEE Trans.Microwave Theory Tech.,vol.32,pp.461-463,1985．
[18] Toshio Onodear and Wayne Raub,"Phase velocity dispersion of a Generalized metal-segment-loaded helix as used in broad-band traveling-wave tubes",IEEE Trans.Electron Devices.vol.35,pp.533-538,1988．
[19] C.L.Kory,J.A.Dayton,"Effect of helical slow-wave circuit variations on TWT cold-test characteristics",IEEE Trans.Electron Devices,vol.45,pp.972-976,No.4,1998．
[20] S.D'Agostino,F.Emma,C.Paoloni,"Sensitivity analysis of TWT's small signal gain based on the effect of rod shape and dimensions",IEEE Trans.Electron Devices,vol.47,pp.1457-1462,No.7,2000．
[21] P.K.Jain and B.N.Basu,"The inhomogeneous dielectric loading effects of pratical helix supports on the interaction impedance of the slow-wave structure of a TWT",IEEE Trans.Electron Devices,vol.39,pp.727-732,No.3,1992．
[22] P.K.Jain and B.N.Basu, "The effect of conductivity losses on propagation through the helical slow-wave structure of a traveling -wave tube", IEEE Trans. Electron Devices, vol.35, pp.549-558, No.4, 1988.
[23] P.K.Jain and B.N.Basu, "The inhomogeneous loading effects of pratical dielectric supports for the helcal slow-wave structure of a TWT", IEEE Trans. Electron Devices, vol.34, pp.2643-2648, No. 12, 1987.
[24] 樊孝年，邬显平，“螺旋线慢波结构损耗特性研究”，真空电子技术，No3，p1-9，2000
[25] 张勇 莫元龙 周晓岚 李建清，“实用翼片加载螺带慢波结构特性研究”，中国电子学会真空电子学分会第十三届学术年会论文集，贵阳，P165-169，2001年
[26] 刘盛纲，李宏福，王文祥，莫元龙，《微波电子学导论》，北京：国防工业出版社，1985．
[27] 张克潜，李德杰，《微波与光电子学中的电磁理论》，北京：电子工业出版社，1994．
[28] 李晓梅等，《科学计算可视化导论》，长沙：国防科技大学出版社，1996．
[29] 石教英，蔡立文，《科学计算可视化算法与系统》，科学出版社，1996．
[30] 张兆镗《微波管高频系统的测量》，北京：国防工业出版社，1982．
[31] 魏彦玉 一类新型慢波系统——螺旋槽结构的理论与实验研究，[博士学位论文]．成都：电子科技大学高能所，2000．
[32] 徐林 行波管CAD网络计算环境及科学可视化研究，[博士学位论文]成都：电子科技大学高能所，1999．
[2] E.F.Belohoubek,"Helix support structure for ultra-wide-band traveling-wave tubes," RCA Rev.,vol.26,pp.106-117,Mar.1965．
[3] R.S.Raju,S.N.Joshi,B.N.Basu,"Modeling of Practical Multi-Octave-Band Helical Slow-Wave Structure of a Traveling-Wave Tube for Interaction Impedance",IEEE Trans.Electron Devices,Vol.39,pp.996-1001,No.4,Apr.1992．
[4] S.Sensiper,"Electromagnetic wave propagation on helical structures",Proc.I.R.E,43(1955) ,149-161．
[5] P.K.Tien,"Traveling-Wave Tube Helix Impedance",Proc.I.R.E,pp.1617-1623,Nov.1953．
[6] S.Ghosh,P.K.Jain,and B.N.Basu,"Rigorous tape analysis of inhomogeneously-loaded helical slow-wave structures",IEEE Trans.Electron Devices,vol.44,ppl 158-1168,1997．
[7] S.D'Agostino,F.Emma,and C.Paoloni,"Accurate Analysis of Helix Slow-Wave Structure" IEEE Trans.Electron Devices,vol.45,pp.1605-1613,No.7 ,Jul 1998．
[8] D.Chernin,T.M.Antonsen,and B.Levush,"Extract Treatment of the Dispersion and Beam Interaction Impedance of a Thin Tape Helix Surrounded by a Radially Stratified Dielectric",IEEE Trans.Electron Devices,vol.46,pp1472-1483,No.7,Jul 1999．
[9] 王自成，陈庆有，吴鸿适，“带状螺旋慢波结构色散的研究”，电子学报， vol.27,No3,pp40-44,1999．
[10] H.P.Freund,"Three-Dimensional Nonlinear Theory of Helix Traveling-Wave Tubes",IEEE Trans.Plasma Science,vol.28,pp.748-759,No.3,Jun 2000．
[11] S.F.Paik,"Design formulas for helix dispersion shaping",IEEE Trans.Electron Devices,vol.16,pp.1010-1014． Dec.1969．
[12] N.P.Kravchenko, L.N.Loshakov, and Y.N.Pchel'nikov, "Computation of Dispersion
Characteristics of a Spiral Placed in a Screen with Longitudinal Ribs", Radio Eng.Electron.Phys.,vol21,pt.1,pp.33-39,Apr.1976．
[13] L.Kumar,R.S.Raju,S.N.Joshi,and B.N.Basu,"Modeling of aVane-Loaded Helical Slow-Wave Structure for Broad-Band Traveling-Wave Tubes",IEEE Trans.Electron Devices,vol.36,pp1991-1999,No.9,Sept 1989．
[14] C.L.Kory,J.A.Dayton,"Computational Investigation of Experimental Interaction Impedance Obtained by Perturbation for Helical Travel ing-Wave Tube Structures",IEEE Trans.Electron Devices,vol.45,pp.2063-2071,No.9,Sept 1998．
[15] S.F.Paik,"Design formulas for helix dispersion shaping ",IEEE Trans.Electron Devices,vol.l6,ppl010-1014,1969．
[16] A.S.Gilmour,M.R.Gillette,Jenn-Tsung Chen,"Theoretical and experimental TWT helix loss determination",IEEE Trans.Electron Devices,vol.10,pp1581-1588,1979．
[17] B.N.Basu,B.B.Pal,V.N.Singh.and N.C.Vaidya,"Optimum design of a potentially dispersion-free helical slow-wave circuit of a broadband TWT",IEEE Trans.Microwave Theory Tech.,vol.32,pp.461-463,1985．
[18] Toshio Onodear and Wayne Raub,"Phase velocity dispersion of a Generalized metal-segment-loaded helix as used in broad-band traveling-wave tubes",IEEE Trans.Electron Devices.vol.35,pp.533-538,1988．
[19] C.L.Kory,J.A.Dayton,"Effect of helical slow-wave circuit variations on TWT cold-test characteristics",IEEE Trans.Electron Devices,vol.45,pp.972-976,No.4,1998．
[20] S.D'Agostino,F.Emma,C.Paoloni,"Sensitivity analysis of TWT's small signal gain based on the effect of rod shape and dimensions",IEEE Trans.Electron Devices,vol.47,pp.1457-1462,No.7,2000．
[21] P.K.Jain and B.N.Basu,"The inhomogeneous dielectric loading effects of pratical helix supports on the interaction impedance of the slow-wave structure of a TWT",IEEE Trans.Electron Devices,vol.39,pp.727-732,No.3,1992．
[22] P.K.Jain and B.N.Basu, "The effect of conductivity losses on propagation through the helical slow-wave structure of a traveling -wave tube", IEEE Trans. Electron Devices, vol.35, pp.549-558, No.4, 1988.
[23] P.K.Jain and B.N.Basu, "The inhomogeneous loading effects of pratical dielectric supports for the helcal slow-wave structure of a TWT", IEEE Trans. Electron Devices, vol.34, pp.2643-2648, No. 12, 1987.
[24] 樊孝年，邬显平，“螺旋线慢波结构损耗特性研究”，真空电子技术，No3，p1-9，2000
[25] 张勇 莫元龙 周晓岚 李建清，“实用翼片加载螺带慢波结构特性研究”，中国电子学会真空电子学分会第十三届学术年会论文集，贵阳，P165-169，2001年
[26] 刘盛纲，李宏福，王文祥，莫元龙，《微波电子学导论》，北京：国防工业出版社，1985．
[27] 张克潜，李德杰，《微波与光电子学中的电磁理论》，北京：电子工业出版社，1994．
[28] 李晓梅等，《科学计算可视化导论》，长沙：国防科技大学出版社，1996．
[29] 石教英，蔡立文，《科学计算可视化算法与系统》，科学出版社，1996．
[30] 张兆镗《微波管高频系统的测量》，北京：国防工业出版社，1982．
[31] 魏彦玉 一类新型慢波系统——螺旋槽结构的理论与实验研究，[博士学位论文]．成都：电子科技大学高能所，2000．
[32] 徐林 行波管CAD网络计算环境及科学可视化研究，[博士学位论文]成都：电子科技大学高能所，1999．