螺旋线慢波结构损耗特性研究

本文采用了与其他作者不同的理论模型和计算方法,对螺旋线慢波结构损耗准确的理论分析,考虑了介质夹持杆,管壳和螺旋线金属电导率对损耗的影响。在ＨＰ８５１０矢量网络分析仪上对两种结构的损耗进行了测量,并对螺旋线与能量耦合器之间的阻抗失配引起的误差进行了修正。理论结果与测量结果有较好的一致性。     

正弦波纹太赫兹慢波结构高频特性研究

针对真空电子太赫兹辐射源的发展需要,本文分析和设计了一种微型正弦波纹慢波结构。利用三维电磁仿真软件研究并分析了其高频特性,并对主要结构参数进行了优化,给出了不同参数下的色散特性和耦合阻抗。仿真结果表明:增加波纹深度可降低电磁波相速,同时增大耦合阻抗;缩短周期长度可提高工作频率;增大横截面宽度可降低相速;降低电子注高度可提高耦合阻抗等。     

一种新型圆弧形螺旋槽慢波结构的色散特性

本文提出了一种新型的大功率行波管慢波结构－圆弧形螺旋槽系统;采用近似的场论方法,得到了该结构的色散方程;讨论了主模在其中的传播情况和系统结构参数变化对色散特性的影响。     

亚毫米波折叠波导慢波结构的损耗特性研究

损耗是慢波结构的重要参量之一.采用理论与仿真的方法分析了在亚毫米波段(220 GHz)折叠波导慢波结构的导体损耗.在理论模型计算了弯曲波导段的衰减系数,并考虑了波导内表面粗糙度对电导率的影响,从而使模型更接近实际情况.计算结果表明,弯曲波导段的衰减常数大于直渡导段,而且理论模型计算出的每周期折叠波导电路的损耗与高频仿真软件HFSS的结果吻合较好,说明理论模型有较高的精确度.在此基础上,分析了慢渡结构参数变化对损耗的影响.     

Ka波段毫米波耦合腔慢波结构高频特性的实验研究

通过对Ka波段毫米波耦合腔慢波结构进行的实验研究,对比了在两种较典型的色散情况下所对应的高频特性的差异,并进一步探讨了耦合腔慢波结构在不同色散情况下所对应的高频特性的基本规律,最后还列举了进一步改进耦合腔慢波结构高频特性的有效途径,可以为今后的设计工作提供必要的参考。     

梯形慢波结构的研究

梯形慢波结构是应用于中功率和大功率行波管的一种重要且实用的周期慢波系统,具有结构简单,成本低,功率容量大,散热性好等优点。目前,国内外对梯形慢波结构的研究工作一直在进行中。分析了梯形慢波结构模型,分析了谐振法在运用CST 软件本征模求解器计算色散特性中的理论和过程。在此基础上,设计了工作点为100GHz 和225GHz 的梯形慢波结构尺寸,并研究了梯形慢波结构的尺寸对色散特性的影响。     

行波管慢波系统的新进展—全金属慢波结构

作为大功率，中等带宽行波管用慢波线，全金属慢波系统具有突出的优越性，尤其适合在毫米波行波管中的应用。本文论述了各种新型全金属慢波结构的发展动态，着重介绍了螺旋槽慢波线的基本理论，提出了在我国开展这一领域研究的必要性。     

太赫兹交错栅慢波结构高频特性理论研究

基于本征函数法对G波段交错栅慢波结构的高频特性建立了理论模型,考虑空间谐波级数项收敛后,计算得到了色散曲线和耦合阻抗以及损耗参量并采用仿真软件对计算结果进行了验证.对比发现理论模型计算的高频特性与仿真结果吻合较好,色散误差小于0.1％,耦合阻抗误差小于10％,损耗误差小于10％,可信度较高.研究结果表明,该模型对于拥有...     

大功率π型慢波结构的特性研究

采用π型慢波结构的大功率行波管具有１５％带宽，无“兔耳”效应以及可实现１００ｋＷ甚至更高的峰值功率，本文运用场匹配法对行波管用的π型慢波结构进行了理论分析，给出了这种结构的色散方程和耦合阻抗，对π型慢波结构进行精细冷测后表明，计算机数值计算的理论值与冷测实验结果吻合良好，为使行波管单模工作而在π型结构中增加搭扣带后的主模色散计算方法也已给出，并取得了与实测较一致的满意结果，本文还叙述了该结构的尺寸     

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。     

一种开敞式脊加载折叠波导慢波电路的高频特性

提出了一种开敞式脊加载折叠波导慢波结构.通过除去直波导段周围的金属边界,形成一种开敞式结构以减弱色散,同时在直波导段加脊以提高耦合阻抗.研究表明,和传统结构相比,新型结构在不影响带宽的前提下,有效提高了耦合阻抗,尤其在大功率设计情况下,耦合阻抗的提高接近1倍.     

A simple equivalent circuit analysis of rectangular folded-waveguide slow-wave structure

A simple yet accurate equivalent circuit model was developed for the analysis of slow-wave properties (dispersion and interaction impedance characteristics) of a rectangular folded-waveguide slow-wave structure. Present formulation includes the effects of the presence of beam-hole in the circuit, which were ignored in existing approaches. The analysis was benchmarked against measurement as well as with 3D electromagnetic modeling using MAFIA for two typical slow-wave structures operating in Ka- and Q-bands, and close agreements were observed. The analysis was extended for demonstrating the effect of the variation of beam-hole radius on the RF interaction efficiency of the device.     

Analysis of Helix Slow Wave Structure for High Efficiency Space TWT

This paper describes the analysis of helix slow-wave structure (SWS) for a high efficiency space traveling wave tube that is carried out using Ansoft HFSS and CST microwave studio, which is a 3D electromagnetic field simulators. Two approaches of simulating the dispersion and impedance characteristics of the helix slow wave structure have been discussed and compared with measured results. The dispersion characteristic gives the information about axial propagation constant (Beta). Which in turn yields the phase velocity at a particular frequency. The dispersion and impedance characteristics can be used in finding the pertinent design parameters of the helix slow-wave structure. Therefore a new trend has been initiated at CEERI to use Ansoft HFSS code to analysis of the helix slow wave structure in its real environment. The analysis of the helix SWS for Ku-band 140W space TWT has been carried out and compared with experimental results, and found is close agreement.     

Design of Tip Loss Profile on Support Rod for a Helix TWT

This paper describes the design of tip loss profile on support rod for a high gain, high efficiency helix TWT. The tip loss profile at sever ends for the input and the output section of the helix slow wave structure has been designed for return loss at severs ends better than -20 dB. The experimental results have been carried out in the input and the output section of the helix assemblies for the high gain helix TWT to find the return loss in the region of carbon coated tip loss on the support rods. The experimental result has been compared with the simulated performance for the return loss at the sever ends. The design of tip loss profile on the support rod for helix TWT has been carried out in real situation using Ansoft HFSS. A good agreement has been found in the simulated and experimental results.     

A Simple and Accurate Analysis of Conductivity Loss in Millimeter-Wave Helical Slow-Wave Structures

Electromagnetic field analysis of a helix slow-wave structure was carried out and a closed form expression was derived for the inductance per unit length of the transmission-line equivalent circuit of the structure, taking into account the actual helix tape dimensions and surface current on the helix over the actual metallic area of the tape. The expression of the inductance per unit length, thus obtained, was used for estimating the increment in the inductance per unit length caused due to penetration of the magnetic flux into the conducting surfaces following Wheeler’s incremental inductance rule, which was subsequently interpreted for the attenuation constant of the propagating structure. The analysis was computationally simple and accurate, and accrues the accuracy of 3D electromagnetic analysis by allowing the use of dispersion characteristics obtainable from any standard electromagnetic modeling. The approach was benchmarked against measurement for two practical structures, and excellent agreement was observed. The analysis was subsequently applied to demonstrate the effects of conductivity on the attenuation constant of a typical broadband millimeter-wave helical slow-wave structure with respect to helix materials and copper plating on the helix, surface finish of the helix, dielectric loading effect and effect of high temperature operation – a comparative study of various such aspects are covered.     

Equivalent Circuit Analysis of Serpentine Folded-waveguide Slow-wave Structures for Millimeter-wave Traveling-wave Tubes

A simple equivalent circuit model for the analysis of dispersion and interaction impedance characteristics of serpentine folded-waveguide slow-wave structure was developed by considering the straight and curved portions of structure supporting the dominant TE ₁₀-mode of the rectangular waveguide. Expressions for the lumped capacitance and inductance per period of the slow-wave structure were derived in terms of the physical dimensions of the structure, incorporating the effects of the beam-hole in the lumped parameters. The lumped parameters were subsequently interpreted for obtaining the dispersion and interaction impedance characteristics of the structure. The analysis was simple yet accurate in predicting the dispersion and interaction impedance behaviour at millimeter-wave frequencies. The analysis was benchmarked against measurement as well as with 3D electromagnetic modeling using MAFIA for two typical slow-wave structures (one at the Ka-band and the other at the W-band) and close agreement observed.     

螺旋带径向厚度对色散和耦合阻抗的影响

该文将有限厚度的实际螺旋带等效为存在无限薄螺旋带的等厚真空层,从场分析和软件模拟两个方面研究了等效慢波结构的色散特性和耦合阻抗.将理论计算、软件模拟和实验测试结果进行了比较,结果表明,用真空层等效有限厚度的实际螺旋带时,将无限薄螺旋带置于等厚真空层的中央,其螺旋慢波结构的色散特性和耦合阻抗的理论计算、软件模拟和实验测试结果三者取得了很好的一致.     

应用于行波管的新一代高压电源设计

介绍了一种应用于行波管的高压开关电源电路,采用降压电流馈入型全桥变换电路,可有效降低高压变压器漏感对效率的影响。试验结果证明该电路能达到高可靠、高效率的要求。     

行波管自动测试设备控制与保护系统

介绍了一种行波管自动测试设备控制与保护系统,系统采用工业控制计算机(简称工控机)作为主控平台,单片机电路作为实时控制与保护下位机,提供行波管高压电源所需的电压基准和调制器所需的定时信号,实现电路各项数据的采样保护.工控机软件采用Visual Basic语言编程,下位机软件采用C语言编程,软件结构模块化设计,通过友好的操作界面对行波管进行自动测试.