Design of Coupling Structure for MMW Folded Waveguide TWTs

A significant advantage of the folded wave traveling wave tube (TWT) is simple coupling structure. In millimeter wave band, owing to higher frequency, linear double taper can be used as impedance transformer. The design method and calculation results for the folded waveguide TWTs in Kα-band are given.     

新型大功率毫米波螺旋线行波管高频系统研究

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。     

曲折矩形槽波导慢波系统的高频特性

对曲折矩形槽波导新型慢波系统的高频特性进行了研究，通过理论分析和数值计算，得到了它的色散曲线和耦合阻抗，并分析了结构参数变化时对色散特性和耦合阻抗的影响。曲折矩形槽波导结合了曲折波导散热能力强、色散特性好、容易加工和矩形槽波导单模工作、低损耗、大尺寸等优点，因此这种新型的慢波系统有可能在毫米波及亚毫米波段的行波管中具有较好的发展前景。     

0.41 THz折叠波导慢波结构分析与设计

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。     

基于MAFIA软件的螺旋线慢波结构冷特性仿真

利用MAFIA软件所提供的准周期边界条件,对两种不同夹持结构的螺旋线行波管一个周期结构的色散和耦合阻抗特性进行了仿真,并与国内开发的螺旋线行波管计算软件包的计算结果进行了比较,为今后进一步优化螺旋线行波管的慢波结构打下基础.     

毫米波功率行波管工作电压的限制因素

本文分析了毫米波功率行波管工作电压与主要限制因素 ,结合具体的高频慢波结构估算了典型管子所能达到的水平 ,并给出了有关评价系数和计算公式 ,可以为设计毫米波功率行波管的高频慢波结构提供参考。     

毫米波行波管金刚石夹持高频结构的设计和优化

利用TWTCAD软件和美国一维螺旋线行波管大信号计算程序对金刚石夹持高频结构和氧化铍高频结构进行了模拟计算,模拟结果表明采用金刚石作为夹持材料可以大大提高高频结构的耦合阻抗和电子效率,同时在采用非均匀输出线路设计时,金刚石结构对电子效率的提高更为明显。     

S、C、X波段螺旋线慢波结构的宽频带行波管研究

为满足现代信息化战争对宽带行波管的需求,对S、C、X波段螺旋线行波管慢波结构的性能进行了研究分析.为适应宽频带要求,选用了带有T形加载翼片以及品形氮化硼夹持杆的螺旋线慢波结构;通过采用动态速度渐变技术,得到了较高的电子效率,并根据仿真计算结果成功研制出了S、C、X波段螺旋线行波管样管.     

毫米波耦合腔行波管高频系统的基本特点与工艺结构综述

根据国外有关文献资料并结合工作实践,对毫米波耦合腔行波管高频系统的基本特点以及有关的工艺结构问题进行邀请赛,可供从事这方面研究工作的人员参考。     

螺距对螺旋慢波系统色散和耦合阻抗的影响

螺距是慢波系统的一个重要参数,直接影响螺旋慢波系统的色散特性和耦合阻抗.严格求解螺距对慢波系统色散和耦合阻抗的影响是不方便的,而通过计算机模拟可以方便快速地研究螺距对慢波系统色散和耦合阻抗的影响.模拟结果表明,对于工程项目当螺距变化小于4%时,螺距对色散和耦合阻抗的影响是很小的.     

螺旋线行波管三维CAD技术进展

介绍了螺旋线行波管三维CAD技术的国际国内研究现状；对目前主流的部分螺旋线行波管三维CAD软件(MICHELLE、COCA、CTLSS、CHRISTINE等)进行了简单介绍。展望了螺旋线行波管CAD技术的发展前景，对我国如何自主开发螺旋线行波管三维CAD软件提出了一些建议。     

Slow-Wave Characteristics of a Frame–Rod Structure Based on Micro-Fabricated Technology for THz Vacuum Electron Devices

A simple equivalent circuit analysis of the frame–rod slow-wave structure (SWS) on dielectric substrates of a traveling-wave tube (TWT) is developed, using the quasi-TEM approximation approach for the dispersion and coupling impedance characteristics of the structure. Moreover, the obtained complex dispersion equation and coupling impedance are numerically calculated. The calculation results by our theory method agree well with the results obtained by the 3D EM simulation software HFSS. It is shown that the dispersion of the frame–rod circuit is decreased; the phase velocity is reduced and the bandwidth becomes greater, while the coupling impedance decreases after filling the dielectric materials in the frame–rod SWS. In addition, a comparison of slow-wave characteristics of this structure with a rectangular helix counterpart is made. As a planar slow-wave structure, this structure has potential applications in compact TWTs based on the micro-fabrication technology, which could be scaled to millimeter wave, even to THz frequency.     

Investigation of Double-groove Loaded Folded-Waveguide Slow-wave Structure for Millimeter Traveling-wave Tubes

To enhance the strength of beam-wave interaction and improve the performance of gain, the double-groove loaded folded-waveguide slow-wave structure (SWS) is proposed for millimeter traveling-wave tubes (TWTs). In the first part, the expressions for the dispersion and the interaction impedance of this novel structure are obtained by using matching conditions of the RF fields. Ansoft HFSS is also used to calculate the high frequency characteristics. The simulation results from HFSS agree with the theoretical results. Numerical calculation for different combinations of the groove width and depth is carried out to study the influence of groove loading on the properties of this novel circuit. In the second part, a linear theory of a double-groove loaded folded-waveguide TWT is developed and calculated for analyzing the effect of groove dimensions on the property of small signal gain. The investigation results indicate that the interaction impedance is obviously raised up and the small signal gain are enhanced by loading groove in the FWSWS.     

新型毫米波大功率器件——折叠波导行波管

折叠波导行波管是近年来涌现的一类新型毫米波大功率器件。它具有宽频带和大功率的优点,制造成本低,且可以与微波功率模块（MPM）组合实现小型化;由于紧凑的整体极靴,能对低电压电子注聚焦,因而很适合要求轻重量的场合。折叠波导行波管在短厘米波段和毫米波段具有极好的发展前景。     

Numerical design of a 100 W, 38 dB gain,W-band multi-section serpentine waveguide vacuum electronic TWT

The serpentine waveguide circuit is a robust beam-wave interaction circuit for W-band TWTs. Here presented the electromagnetic properties and design methodology for W-band multi-section SWG traveling wave tube. Cold-test (in absence of electron beam) numerical design performed theoretically and further optimized/validated with standard simulation code to predict the dispersion, interaction impedance, ohmic-loss and small-signal gain. Numerical simulation for the quarter wave transformer couplers with SWG circuit geometry shown the return-loss less than −20 dB for the 5% frequency band. Later, in systematic manner, hot-test (in presence of electron beam) numerical design performed for multi-section TWT by using standard particle-in-cell 3-D simulation code. The three section, 60 periods SWG TWT predicted peak radiation power 130 W at target frequency 94 GHz, 39.5 dB saturated gain, 5.3% instantaneous 3-dB frequency bandwidth, and 6.5% electronic efficiency.     

一种有限厚度翼片加载螺旋线色散特性及耦合阻抗研究

翼片加载螺旋线慢波结构广泛应用于大功率、宽频带行波管中.一般的计算未考虑翼片加载所引起的角向空间谐波,本文考虑空间谐波,建立了有限厚度翼片加载螺旋线慢波结构的模型,推导出实用的色散方程和耦合阻抗表达式.利用导出的方程对实际行波管的螺旋慢波结构进行计算,并与测量结果和简单翼片模型进行了比较.首次通过分析的方法得到加载翼片有最佳中心夹角(θ)存在.     

Ka波段500W脉冲空间行波管研制

针对空间探测领域的应用需求,本文采用大功率返波振荡抑制技术以及过渡波导输能技术,设计出了一种Ka波段580 W脉冲空间行波管。经过实际的样管测试验证,功率≥580 W,饱和增益≥47 dB,实现了Ka波段500 W脉冲空间行波管主要技术参数。     

A Fast Computation Technique for RF Performances in Broadband Millimeter Wave Helix TWTs

A computation technique for gain, efficiency and output power in broadband millimeter wave helix TWTs from their dimensions is described. The computed results by modeling are good agreement with experimental measurements. It is shown that the method is fast and useful accuracy. It can be used as engineering design for MMW TWTs.     

引起行波管增益幅度相位波动的一种原因

无内反射的理想行波管小信号和大信号互作用理论不能解释行波管的增益和相移随频率快速波动的现象,但这种现象在行波管中不同程度地存在,并严重影响行波管的总体性能,特别是影响行波管幅度和相位的一致性.本文通过对具有高频不连续性的行波管进行建模分析,用表征不连续性的反射系数的幅度给出了行波管增益和相移峰-峰值的量级,对控制相位一致性行波管的不连续性提供了依据.     

Power combining characteristics of backed-off traveling wave tubes for communications applications

Traveling wave tubes (TWTs) used in multi-tone and digital communications applications are typically operated backed off from saturation in order to improve the amplifier linearity. This reduces the bit error rate (BER), decreases intermodulation distortion and lowers adjacent channel power; all at the expense of reducing the average output power. For emerging telecommunications applications, the average power requirement is increasing to provide higher bit rates and lower BER, and often exceeds the power obtainable from backed-off space or telecommunications TWTs. One solution is to power combine TWTs that are operated 3 to 10 dB backed off from saturation. Efficient power combining requires that the phase and gain of the signal from each TWT be closely matched. To understand the variation in these parameters across a build-set of tubes, the phase and gain versus drive of 35 Boeing S-band 5525H TWTs were measured. The standard deviation in the phase about the mean phase shift measured at saturation was found to be 2.6/spl deg/, with a related standard deviation of the gain compression at saturation of 0.22 dB. These levels result in small power combining losses and small errors in phased-array fed multi-beam antennas in broadband multi-tone applications.