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Shunkang Liu 《Journal of Infrared, Millimeter and Terahertz Waves》2002,23(6):899-906
The efficiency enhancement methods for helix and coupled cavity traveling wave tube (TWT) in millimeter wave (MMW) are described. The interaction efficiency has been reached 14.56% by dynamic velocity taper in Ka-band TWT. Efficiency improvement has been carried out by used copper helix for broadband MMW TWT. Owing to a ferruleless coupled cavity TWT used phase-adjusted taper, the interaction efficiency has been increased from 9.6 to 22.6%. Finally, enhancing collector efficiency used multistage depressed collectors is discussed in the paper. These concept and technology of the approach are very useful for tube designer. 相似文献
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Shunkang Liu 《Journal of Infrared, Millimeter and Terahertz Waves》2000,21(4):655-660
Folded waveguide circuit (FWC) is an ideal slow wave structure for broadband power traveling wave tube (TWT) in millimeter wave. But owing to changes of propagating character by reflecting of waveguide bend and electron beam hole, stopband can be formed. On the basis of computation of the stopband, effects of the dimension of FWC on stopband width are analyzed. It is available for design in FWC TWT. 相似文献
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该文探讨了CVD金刚石材料在宽带毫米波螺旋线行波管中的应用,研究了两类非杆状新型CVD金刚石夹持的螺旋线高频结构,利用MAFIA分析了它们的色散特性、耦合阻抗和衰减常数,与传统的矩形BeO夹持杆和矩形CVD夹持杆高频结构进行了对比,最后将这两类新型高频结构替代国内某毫米波行波管(26-40GHz)中的矩形BeO夹持杆螺旋线高频结构,利用宽带大功率行波管CAD集成环境中的注波互作用模块分析了其大信号工作特性。结果表明,分立CVD金刚石夹持高频系统兼顾了超宽带和大功率,同时由于金刚石直接和螺旋线及金属翼片大面积接触,该结构还具有极好的散热能力,是一种有重要应用前景的高频结构。 相似文献
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Shunkang Liu 《Journal of Infrared, Millimeter and Terahertz Waves》2000,21(6):915-920
The characteristics of two kinds of bifilar helix circuit are discussed in this paper. One is alike wound bifilar helix and another is contrawound bifilar helix. Alike wound bifilar helix is often used in O-type backward wave tube (BWO). Owing to wider operating bandwidth, higher interaction impedance and large dimensions, the contrawound helix is suitable for broadband millimeter wave traveling wave tube (MMW TWT). 相似文献
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Shunkang Liu 《Journal of Infrared, Millimeter and Terahertz Waves》2002,23(10):1445-1453
The high power broadband amplifiers are key devices for millimeter wave system and equipment. The significant progresses for broadband amplifier–high power TWT in MMWs are described. Advanced techniques such as enhancing operating bandwidth, reducing cost, increasing efficiency, improving heat transfer capability, suppressing spurious oscillations and raising beam transmission have been developed. These approaches possess important consult value to designer for MMW power amplifiers. 相似文献
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折叠波导慢波结构太赫兹真空器件研究 总被引:7,自引:0,他引:7
简要介绍了利用折叠波导慢波结构的太赫兹真空辐射源的发展现状,重点对折叠波导慢波结构的特点进行了研究,并利用这种慢波结构开展了W、D波段行波管,W波段和650GHz返波振荡器,560GHz反馈振荡放大器的设计、计算和模拟优化,分别得到了较好的结果,并实际研制出W波段连续波行波管,输出功率达到8W。对太赫兹真空辐射源的部件技术、微细加工技术进行了研究和分析。 相似文献
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Hyun-Jun Ha Soon-Shin Jung Gun-Sik Park 《Journal of Infrared, Millimeter and Terahertz Waves》1998,19(9):1229-1245
A wideband folded waveguide traveling-wave tube (TWT) amplifier has advantages of simpler coupling structures and robust structure over the conventional helix TWT. The phase velocity of waves in folded waveguide is slowed down to the velocity of electron beam. Slow-wave interaction with the electron beam in folded waveguide is studied in a linear fashion. For a cold beam, the linear theory predicts a gain of 2 dB/cm and a bandwidth of 37% at the center frequency of 14 GHz. A closed algebraic dispersion relation for the frequency and the axial phase shift per period is obtained using an equivalent circuit model. Numerical solution calculated from the dispersion relation and three-dimensional electromagnetic code, HFSS simulations predict a mode coalescing in the folded waveguide. And a theoretical phase velocity prediction of the electromagnetic wave in this circuit is verified by HFSS simulations. 相似文献
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提出一种改进的曲折槽波导—曲折双脊槽波导提高太赫兹行波管的功率和带宽.针对这种新型慢波结构设计了一种新的传输波导作为输入输出能量耦合器.从高频特性仿真结果可以发现曲折双脊槽波导可以提高耦合阻抗并扩展带宽.此外, 粒子仿真结果表明当电子注加载27.4kV电压和0.25A电流时, 新型曲折双脊槽波导行波管在中心频率340GHz处输出功率能达到65.8W同时对应增益27.21dB.因此, 曲折双脊槽波导行波管可以用作宽带和高功率太赫兹辐射源. 相似文献
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Shunkang Liu 《Journal of Infrared, Millimeter and Terahertz Waves》1999,20(5):859-865
Backward wave oscillation can be troublesome in high power helix TWT, especially millimeter wave helix traveling wave tubes (MMW HTWT's). To suppress these oscillations, start-oscillation current of backward wave has to know when MMW HTWT's are designed. A fast computation of the start-oscillation current for MMW HTWT's is presented. It is shown that the computed values are agreed with the experimental results in Ka band. 相似文献
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在0.14 THz,0.22 THz和0.34 THz折叠波导行波管研制的基础上,讨论了0.41 THz折叠波导行波管慢波结构设计与加工的可行性,分析研究了折叠波导慢波结构弯曲处直角弯曲与半圈弯曲、方形电子注通道与圆形电子注通道对色散特性、耦合阻抗、带宽、冷损耗和增益的影响。考虑了慢波结构中增加理想衰减器对该行波管带宽和增益的影响,得到了0.41 THz折叠波导行波管慢波结构的初步设计方案,为太赫兹折叠波导行波管的继续发展打下了一定基础。 相似文献
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Guo Guo Yanyu Wei Lingna Yue Yubin Gong Xiong Xu Jun He Guoqing Zhao Wenxiang Wang Gun-Sik Park 《Journal of Infrared, Millimeter and Terahertz Waves》2012,33(2):131-140
This paper presents a tapered ridge-loaded folded waveguide (FWG) slow-wave structure (SWS) for broadband and high power millimeter
wave traveling wave tube (TWT). The radio-frequency characteristics including dispersion properties, interaction impedance,
S-parameters are analyzed. And based upon these results, the nonlinear large signal performance of the tapered ridge-loaded
folded waveguide TWT working in W-band is simulated by 3-D particle-in-cell code. In the same ridge length, the tapered FWG
has lower reflection and radio-frequency loss than the normal ridge-loaded FWG. Besides, the tapered ridge-loaded FWG TWT
also has higher electron efficiency and larger bandwidth, which is more suitable for millimeter-wave TWT. 相似文献
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本文在分析传统耦合腔慢波结构的基础上,提出了一种具有低电压大功率特点的耦合腔慢波结构。该慢结构可以充分利用传统耦合腔慢波结构的成熟工艺,是一种非常有发展前途的毫米波慢波结构。 相似文献
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In this paper, we analyze the design of the folded waveguide slow-wave circuit for traveling-wave tube (TWT) amplifiers. On
the basis of physical analyses, an improved physical-based design method that is especially suitable for high-power devices
is developed. The proposed method overcomes the difficulties resulting from increased operating voltages and requirements
for higher interaction impedance in high-power designs. It enables balancing of dispersion and interaction impedance, which
is a flexible approach in addressing operational problems. Furthermore, the essential relationship between the proposed and
the existing methods are revealed. A Ka-band folded waveguide TWT amplifier is designed and examined, thereby confirming that
the new design method is effective and reliable. 相似文献
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Shunkang Liu 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(5):629-638
The pill-box and block RF windows for millimeter wave (MMW) tubes are presented. The pill-box window is suitable for broadband MMW tubes. And the block window can be used for high power tubes in short MMW. The equivalent circuits for two windows are given. To reach better match characteristics in wider operating bandwidth, the optimum design methods for pill-box and block window in MMW tubes are described in this paper. The testing results show that the theoretic computation is fast and useful accuracy. The design methods possess references value to designer for MMW tubes. 相似文献
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为了得到高功率、高频率、大带宽的微波源,运用微波仿真软件CST对矩形耦合腔行波管这一新型的大功率器件进行了粒子模拟,得到了23.7kw的峰值输出功率,并且分析了行波管的工作电压与慢波系统的腔体数量对行波管工作特性的影响。结果表明,矩形耦合腔行波管具有较高的功率承载能力。 相似文献