V波段介质加载梯形慢波结构研究

研究了V波段介质加载梯形慢波结构。通过在耦合槽和间隙处进行适当介质加载,降低主模的相速,改善色散特性。使用CST对其慢波结构进行仿真,得到色散曲线和耦合阻抗,结果表明介质加载对耦合阻抗的影响很小,但却可以明显地降低相速,同时色散特性也更为平坦。     

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。     

CST MWS软件模拟三维螺旋线慢波结构

本文介绍了用CST MWS软件的周期边界条件计算行波管螺旋线慢波结构的色散和耦合阻抗等冷测特性的方法,用采取螺旋带模型的理论分析计算结果和实验测试值加以验证,取得了比较一致的结果;并应用这种MWS的模拟方法和螺旋带模型的计算方法分析了具有扇形和T形夹持杆慢波结构的冷测特性,结果表明,相速和耦合阻抗都随着扇形角度的增大而减小,随着T形窄端宽度的增加而减小,随着T形窄端高度的增加而增大.     

行波管高频参量对二次谐波的影响分析

慢波系统的高频参量决定了行波管的功率和增益特性,谐波与基波频率下的高频参量的关系决定了行波管输出的谐波与基波的比例。本文在较宽的参数变化范围内对比分析相速、耦合阻抗在频带内的不同分布状态对低端的二次谐波比的影响。计算结果表明,相速之比为0.96 附近对应为二次谐波比最大的状态,此变化规律与频率的相关度较小;而谐波与基波的耦合阻抗之比越大,二次谐波比越大。对于宽带行波管,在翼片加载的高频结构中调整翼片内径就可以使输出的二次谐波比产生较大变化。     

螺旋线慢波结构的参数变化对其冷测特性的影响

本文介绍了用MAFIA软件的准周期边界条件计算螺旋线行波管慢波结构的色散和耦合阻抗等冷测特性的方法,并重点对慢波结构中各参数,特别是矩形螺旋线截面的宽度和厚度对其冷测特性的影响进行了分析.这是目前理论上没有解决的难题.分析结果表明,螺旋线的宽度和厚度对其色散影响不大,而对耦合阻抗有一定影响.对耦合阻抗而言,螺旋带宽度和厚度都存在一个最佳值.     

槽区加载介质矩形格栅慢波结构的色散与增益

建立了槽区内加载介质的格栅慢波结构模型.通过Borgnis函数法和场匹配法得到冷态和热态色散方程.并推导了耦合阻抗的表达式.在稀疏电子注的假设下,求得增益近似解的表达式.通过数值方法,求解并分析了加载介质对色散关系、基波耦合阻抗、基波相速和基波增益的影响.并指出分别在槽内加载介质和格栅对侧加载介质对高频特性的不同影响趋势.     

适用于Ka波段圆形电子注行波管的半圆形卷绕微带线慢波结构

提出了一种基于开槽介质基底的卷绕微带线慢波结构.由于金属曲折微带线印制在介质基底的半圆形槽中,这种卷绕微带线慢波结构非常适合圆形电子注行波管,从而使得采用这种新型慢波结构的行波管可以利用传统的周期永磁磁场进行聚焦.文章对提出的卷绕微带线慢波结构的色散特性,耦合阻抗,传输特性及注-波互作用进行了分析.和传统的平面微带线慢波结构相比,提出的卷绕微带线慢波结构具有更低的相速、更弱的色散和更高的耦合阻抗,从而使得其适合于低电压、宽频带、小型化的毫米波行波管.将同步电压及直流电流分别设置为6 550 V及0.1 A的情况下,基于该卷绕微带线慢波结构的Ka波段行波管在35 GHz处能够输出42.32 W的功率,对应增益为26.26 dB,且均匀聚焦磁场只需0.4 T.     

适用于Ka波段圆形电子注行波管的半圆形卷绕微带线慢波结构（英文）

提出了一种基于开槽介质基底的卷绕微带线慢波结构.由于金属曲折微带线印制在介质基底的半圆形槽中,这种卷绕微带线慢波结构非常适合圆形电子注行波管,从而使得采用这种新型慢波结构的行波管可以利用传统的周期永磁磁场进行聚焦.文章对提出的卷绕微带线慢波结构的色散特性,耦合阻抗,传输特性及注-波互作用进行了分析.和传统的平面微带线慢波结构相比,提出的卷绕微带线慢波结构具有更低的相速、更弱的色散和更高的耦合阻抗,从而使得其适合于低电压、宽频带、小型化的毫米波行波管.将同步电压及直流电流分别设置为6 550 V及0.1 A的情况下,基于该卷绕微带线慢波结构的Ka波段行波管在35 GHz处能够输出42.32 W的功率,对应增益为26.26 dB,且均匀聚焦磁场只需0.4 T.     

耦合腔行波管SWS的尺寸变化对冷特性参量的影响

耦合腔行波管(CCTWT)慢波结构(SWS)的冷特性参量包括色散特性、耦合阻抗和分布损耗,是CCTWT研究与设计中的重要参量。本文利用CST微波工作室软件计算了CC TWT的SWS各个尺寸变化对冷特性参量的影响。这些影响不仅对CCTWT的设计有重要意义,而且为进一步研究相速渐变打下基础。     

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。     

大直径波纹内导体同轴慢波结构特性的研究

提出了易以加工的大直径波纹内导体相对论返波振荡器慢波结构,推导了这种慢波结构的冷色散方程和耦合阻抗计算公式,数值计算并详细分析了相关结构参数对TM_0n模式色散曲线分离度以及TM₀₂模式的高频场耦合阻抗的影响.结果表明:慢波结构周期、波纹深度以及电子注平均半径都对高频场耦合阻抗有影响;这种慢波结构在抑制模式竞争、以及在低引导磁场下工作等方面都有较大的优势.     

A Tapered Ridge-loaded Folded Waveguide Slow-wave Structure for Millimeter-wave Traveling-wave Tube

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.     

Analysis of the Coaxial Ridge-Loaded Helical Groove Waveguide

The coaxial ridge-loaded helical groove waveguide is proposed in this paper. As an all-metal slow-wave circuit, it has advantages of good heat dissipation and great size, and thus is suitable for use of millimeter TWT. By means of field theory, the expressions of the dispersion equation and the coupling impedance of the coaxial ridge-loaded helical groove waveguide are obtained. The influence of various circuit dimensions on the dispersion relation and the coupling impedance is investigated by the results of numerical computation.     

Ridge-loaded ladder lines

The Karp structure, anti-Karp structure, and ridge-loaded stub-supported meander line have been analyzed by the Fletcher method and curves of dispersion and interaction impedance are given which are sufficiently comprehensive for most design purposes. The results of measurements on an anti-Karp structure and a ridge-loaded stub-supported meander line are given for comparison with the analysis. The relative merits of the three structures for both forward and backward wave interaction at medium and low voltages are discussed in some detail, and it is concluded that the use of a structure which propagates in the absence of a ridge permits the achievement of greater bandwidth in low voltage BWO's and gives greater design flexibility. It is also shown that the structures may, without significantly altering their circuit properties, be deformed into shapes suitable for use with annular or solid circular beams.     

Conductor geometry independence of phase velocity in TEM-modetransmission lines

Based on Caratheodory's (1952) generalization of the Riemann mapping theorem, it is shown that a proof is possible for the conductor geometry independence of phase velocity in transverse electromagnetic (TEM)-mode transmission lines. Specifically, an effort is made to show that a proof of the invariance of phase velocity with conductor geometry is possible from essentially circuital considerations. The argument implies that it is obvious that any TEM-mode transmission line which consists of two conductors, each of arbitrary section, one totally enclosed within the other, can be transformed into a concentric, right circular, coaxial line. Since solutions of Laplace's equation are invariant under conformal transformation, the inductance and capacitance per unit length of the original and transformed lines must be the same. To establish that fact generally, it remains then only to observe that, for a normal coaxial line, a problem to which there is a simple analytic solution, phase velocity is independent of geometry     

Backward Wave Oscillators With Coaxial Structures: Dispersion Relation and PIC Simulation

The dispersion relation of a corrugated—wall resonator with an inner coaxial structure has been analyzed as well as the effects of the corrugation period, amplitude and the radius of the coaxial structure on it. Furthermore, we got an output power of 2.1GW at frequency 11.09GHz in a non-uniform slow wave structure by using the PIC simulation software—MAGIC.     

Characteristic Impedance of a Rectangular Coaxial Line with Offset Inner Conductor

The singular-integral-equation technique is used to derive the capacitance and, hence, characteristic impedance of a rectangular coaxial line with a zero-thickness inner conductor. The position of the inner conductor is arbitrary, but its orientation is assumed to be parallel to the top and bottom walls of the outer conductor. Simple yet very accurate formulas for the capacitance and characteristic impedance are found in terms of complete elliptic integrals.     

毫米波同轴-波导二极管管座计算机模拟分析

本文从理论上分析了构成功率合成器的主要组件横向耦合同轴-波导二级管管座的结构,建立了它的等效电路模型。并且通过计算机模拟分析,得到腔体短路位置l4。失配负载Z1及其位置l1。腔体输出负载Z3及其位置l3、同轴线内导体半径r以及同轴线段之间的距离等参量与功率比的关系。根据此结果给出毫米波合成器设计的最佳方案。模拟分析已为实验结果所证实。