开放式圆柱光栅周期结构的色散特性分析

研究了一种新的开放式圆柱光栅周期结构,该结构可以作为Smith-Purcell自由电子激光和相对论行波管中的慢波结构.采用近似的场论方法,用一系列相连的矩形阶梯来近似代替光栅上任意槽形的槽的连续轮廓,利用各阶梯面上导纳的匹配,以及槽与互作用区的连续和匹配条件,获得了任意形状槽圆柱光栅周期结构的色散方程,并讨论了系统结构参数变化对系统色散特性的影响.利用软件MAGIC对结构的色散特性进行了二维模拟,与理论计算得到的值符合良好.     

螺旋槽波导特性的计算与模拟研究

计算了螺旋槽波导的色散特性和群速度,用“准周期边界条件”方法和谐振法模拟计算了螺旋槽波导的色散特性,两种方法的模拟结果与计算都比较一致。此外,还模拟测试了渐变与规则螺旋槽波导连接的匹配性能、螺旋槽波导高频系统的传输特性。结果表明,螺旋槽波导是非常适用于回旋行波管的高频结构。     

任意曲线形状介质栅漏波天线辐射特性的分析

本文用多模网络理论与严格场匹配相结合的方法分析了任意周期层形状介质栅漏波天线的辐射特性。文中采用阶梯近似的方法将连续变化的任意曲线形状周期结构分成多个矩形周期结构的组合,从而将问题归结为对多周期层漏渡天线的分析;这就大大简化了复杂边值问题的求解过程。据此系统地研究了周期槽形状对介质栅漏波天线辐射特性的影响。文中给出的曲线可供设计和制造介质栅天线时参考。     

同轴任意槽形周期圆波导慢波结构小信号特性

用阶梯近似的方法分析任意槽形加载的圆波导慢波系统中的场,采用自洽场理论,得到了任意槽形周期加载圆波导慢波系统在小信号条件下的“热”色散方程,并对结构参数对小信号增益的影响情况进行了研究。加载深度和槽口宽度在固定频率下都有一最佳值使得增益最大。     

高频阶梯槽的制作研究

随着电子产品往高频、高速、小型化的发展趋势,高频阶梯槽的设计需求日益旺盛,本文基于高频阶梯槽在常规加工工艺所产生的偏位、流胶、板材损伤问题的突破,对高频阶梯槽的设计可实现性进行研究。     

任意槽矩形波导栅行波管注-波互作用线性理论研究

在带状电子束假设下,采用场匹配和导纳匹配的方法,导出了存在电子束的任意槽矩形波导栅行波管的"热"色散方程,对该方程进行数值求解,得到了小信号增益,分别讨论了慢波结构槽形状和电子束参量对小信号增益的影响,为毫米波矩形波导栅行波管的设计提供了理论依据.     

半球动压气浮轴承有螺旋槽与无螺旋槽轴承特性仿真分析

本文采用CFD数值模拟方法和试验数据相结合的方式对半球型动压气浮轴承径向偏心3%和轴向偏心3%的流场进行分析.对轴承同一偏心率下有、无螺旋槽的轴径向刚度、轴径向承载力、姿态角、功率等特性进行了比较.结果表明,半球型动压气浮轴承的数值仿真结果与试验数据吻合较好.刻有螺旋槽的轴承,压力沿螺旋槽逐渐上升,在螺旋槽顶达到峰值,跨过螺旋槽后压力逐渐降低.由于圆周均布了多个螺旋槽,螺旋槽的导流作用使得高压区均匀的分布在轴承圆周面上.没有螺旋槽的轴承在径向偏心时存在一个对称分布的高压区和低压区,二者夹角近似180度,但在轴向偏心时却无法形成动压效应,轴承支撑力几乎为0.相比无螺旋槽的轴承,有螺旋槽压力分布更均匀,能提供轴、径向支撑力,且姿态角和功率更小,更有助于电机稳定的高速旋转.     

半金属化阶梯槽可靠性研究

针对半金属化阶梯槽加工存在的金属化包边缺损或剥落问题,本文通过正交试验的方式,寻找影响半金属化阶梯槽可靠性的关键因素,对控深槽加工进行控制,解决金属化包边缺损或剥落的工艺问题。     

微带线-槽线馈电缝隙等角螺旋天线设计

被动雷达导引头为探测与跟踪目标可采用宽带等角螺旋天线,针对降低等角螺旋天线剖面,该文提出一种低剖面背腔式微带线-槽线馈电缝隙等角螺旋天线。微带线-槽线巴伦(Balun)中渐变微带线将同轴线激励的不平衡电场最终转化为槽线处平衡电场。实测结果表明,该缝隙等角螺旋天线实现了1:9的电压驻波比(VSWR)带宽,良好的辐射方向图与圆极化特性。在天线背面加入高度仅有0.05L(L为最低工作频率所对应自由空间中波长)的反射腔,腔内放置矩形环状吸波材料,有效拓展了天线低频段带宽。测试结果表明带有反射腔的缝隙等角螺旋天线实现了1:6.4的电压驻波比带宽,天线增益大于4 dB,良好的圆极化与方向图特性。平面化、一体化的馈电方式与低剖面反射腔有效降低了缝隙等角螺旋天线剖面,测试结果验证了该文所提出的微带线-槽线巴伦馈电缝隙等角螺旋天线设计方法的有效性。     

含阶梯插头盲槽的印制板量产制作工艺

对于含阶梯插头盲槽印制电路板的批量生产,本文采用新阻胶制作工艺,可实现盲槽的阶梯插头无残胶,以解决插头处残胶需要大量人工修理的问题,为生产此类难度板提供新的制作方法.     

ANALYSIS OF RECTANGULAR WAVEGUIDE GRATING SLOW-WAVE STRUCTURE WITH THE ARBITRARY SHAPED GROOVES

The rectangular waveguide grating slow-wave structure (SWS) with arbitrary shaped grooves is presented and analyzed in this paper. As an all-metal slow-wave circuit, it has properties that can be used in high-power millimeter-wave or sub-millimeter wave traveling wave tube (TWT). The unified dispersion equation and the expression of coupling impedance are obtained in this paper by means of an approximate field-theory analysis, in which the profile of the groove is approximately replaced by a series of steps and the field continuity at the interface of two neighboring steps together with the field matching conditions at the interface between the groove region and the interaction region are employed. A rectangular groove SWS was manufactured and the cold measurement was made. The experimental data are in good agreement with the numerical calculation. The derived transcendental equations are resolved numerically for four classical structures such as rectangular, dovetail, ladder and cosine. Finally, taking the rectangular waveguide grating SWS with rectangular grooves for example, the influences of physical dimensions on dispersion relation and coupling impedance are discussed.     

Wave Propagation Along a Helical Step-Loaded Groove Waveguide

A new kind of helical groove structure, step-loaded groove waveguide is presented and analyzed in this paper. The dispersion equation of this structure is derived by means of a field-matching method. This equation may be reduced to the dispersion equation of helical ridge-loaded structure and rectangular one. In order to demonstrate the influence of the step on the dispersion properties, the comparison of the dispersion characteristics is made in these helical rectangular and modified rectangular groove structures. Form the analysis, it is shown that the step loading tends to reduce the dispersion of the helical groove circuit and the step-loaded structure has the weaker dispersion compared with the rectangular one or the ridge-loaded one. The effect of the step shape on the wave properties is also discussed under the deep groove case. The theoretical results explicitly indicate that the V-like step-loaded structure has the weakest dispersion in all step-loaded structures.     

Characteristics of Arbitrarily-Shaped Helical Groove Slow-Wave Structure Loaded with a Concentric Dielectric-Rod

The dielectric-rod is loaded on the central axis of the arbitrarily-shaped helical groove slow-wave structure. Meanwhile, the profile of the groove is replaced by a series of continuous rectangular steps. The unified dispersion equation of the arbitrarily-shaped helical groove waveguide loaded with a concentric dielectric-rod is obtained by means of a combination of filed-matching method and admittance-matching technique. Then, the effect of the change of groove shape and the dielectric-rod parameters on the dispersion and coupling impedance is approached by theory calculation. The results show that: loaded with dielectric-rod, the bandwidth of the helical groove traveling wave tube (TWT) is effectively broadened, but the coupling impedance is reduced. Among the five different groove shapes, the triangle-type groove has the widest bandwidth but the smallest coupling impedance, and the swallow-tailed-type groove has the narrowest bandwidth but the largest coupling impedance.     

阶梯加载矩形波导栅慢波系统的研究

提出了一种新型的毫米波行波管慢波结构———阶梯加载矩形波导栅慢波系统.考虑槽区内场的高次项,利用各阶梯相邻面的阶跃条件以及互作用区和加载区的场匹配条件,获得了该结构的色散方程,并导出耦合阻抗.讨论了主模在其中的传播情况,并分析了系统结构参数变化对慢波电路高频特性的影响.数值计算表明加载阶梯的尺寸对此结构内波的传播特性有很大影响,可以根据不同的要求来选取具体设计参数.该结果为进一步研究和设计此类行波管高频系统提供了理论基础.     

Analysis of the circular-arc-shaped helical groove slow-wave structure

This paper concerns a new circular-arc-shaped helical groove all-metal structure, and emphasizes the propagation characteristics of the slow wave. By using approximate field-matching conditions, the dispersion equation and the coupling impedance of this circuit are obtained. The dispersion curves and coupling impedances of the fundamental wave and some harmonics are calculated and the influences of various circuit dimensions are discussed. The calculation results show that the bandwidth can be improved by increasing the arc angle or decreasing the pitch of the structure; a 50% bandwidth is achieved by deviating the phase velocity within ±5%. As a new slow-wave structure for a travelling wave tube, this circuit has an attractive feature, namely the bandwidth is broad while power capacity is high.     

Investigation of the Half-Circular Helical Groove Slow-Wave Structure

As a new type all-metal slow-wave structure of the millimeter wave TWT, The helical groove has a lot of advantages: large power handling capability, large sizes, high precision and moderate bandwidth. Of the helical groove structure, the half-circular helical groove can achieve wider passband than the rectangular helical groove can do. The approximate and much simple matching method of the fields of the half-circular structure is presented in this paper. The more general expressions of the dispersion characteristic and coupling impedence, in which the fast-wave modes and slow-wave modes are considered simultaneously, are obtained. It is indicated from the results of the numerical calculation that choosing suitable dimensions of the structure and suppessing the backward wave osillation, this kind of slow-wave structure can operate over 50% ‘hot’ relative bandwidth.     

Investigation of the Dielectric-Loaded, Ridged Helical Groove Slow-Wave System for the Millimeter Wave TWT

A dielectric-loaded, ridged helical groove slow-wave structure for the millimeter wave traveling wave tube is presented in this paper. The effects of the groove depth, ridge dimensions and the dielectric permitivety on the wave propagating properties and the interaction impedance are investigated in detail. From the analysis, it is indicated that for broader band amplification in a helical groove travelling wave tube, a ridged helical structure with shallow groove and loaded by dielectric with proper relative permitivety may be applied.     

大功率行波管新型慢波线技术的进展

全金属慢波结构由于具有热耗散能力强，功率容量大，比耦合腔慢性线带宽度，结构整体性好，尺寸大等一系列优点而备受人们关注。本文着重介绍了螺旋槽、环板、曲折波导及周期加载波导四类结构的发展现状，包括理论研究与实际应用情况，探讨了新型慢波线在技术上存在的问题及今后的努力方向，指出全金属慢波结构将在毫米波行波管、返波管、毫米波回旋行波管及相对论器件等方面得到广泛应用。     

考虑螺带厚度的纵向导体加载螺旋慢波特性分析

考虑非翼片区角向高次模式以及螺带厚度,运用场匹配方法参考脊加载环板慢波结构的边界条件推导得到翼片加载螺旋慢波结构的色散特性方程;并运用MAFIA软件对该结构进行模拟计算,将理论结果与模拟计算进行比较,其误差范围基本满足设计精度的要求,并讨论了不同翼片结构参数对色散特性的影响,为各种类型的翼片加载螺旋慢波特性的计算提供了一种参考方法。