相对论行波管慢波结构几何参数研究

 推导了无引导磁场下具有离子通道的波纹波导中的色散方程,并通过数值计算分析了该慢波结构的几何参数如波纹周期、波纹深度以及波导平均半径对相对论行波管的带宽及增益的影响,为相对论行波管的设计提供了一定的依据。     

行波管中慢电磁行波与电子注非线性互作用普遍理论

在同时考虑多信号输入和相对论效应的情况下，利用波导激励理论获得了行波管中慢电磁行波与电子注非线性互作用的全三维自洽工作方程组，包括激发方程、运动方程、能量转化方程、相位演化方程等，适合大部分行波管中慢电磁行波与电子注的非线性互作用过程.利用该理论具体分析了一个宽带螺旋线行波管在多信号输入时的交叉调制，并与实验结果进行了比较，验证了理论和计算的正确性.另外，还模拟了一个相对论盘荷波导行波管中的非线性注波互作用过程. 关键词： 行波管 慢电磁行波 非线性注波互作用 交叉调制     

相对论行波管色散特性分析

 数值计算了一种填充等离子体的波纹波导结构的行波管，在强引导磁场下，被一环形相对论电子注驱动的小信号增益。详细地分析了等离子体的浓度、电子注的电压、电流及其在慢波结构中的传输位置对行波管的增益、带宽和中心频率的影响。     

0.14 THz瓦量级折叠波导行波管设计

在本课题组此前采用显式方法设计0.14 THz宽带折叠波导慢波结构的基础上,设计了一种0.14 THz瓦量级输出折叠波导行波管。通过CST MWS软件分析结构尺寸对冷测特性的影响规律来确定一组慢波结构参数,然后对电子枪、永磁聚焦系统、输入输出结构、衰减结构及收集极系统进行设计,最后经过CST PS软件进行整管热测特性仿真模拟。此过程不断迭代,最终找到一组结构参数满足频率在0.14 THz、输入功率为20 mW时,折叠波导行波管输出功率大于6 W。为了验证设计的电子光学系统的正确性,加工装配了一根流通管,并进行了流通率测试,测得流通率大于80%。     

Peculiarities of electron-beam interaction with waves in partially plasma-filled corrugated waveguide

It is shown when the cross-section of a waveguide is partially filled by magnetized plasma, slow and fast E-waves can exist simultaneously at the same frequency, which is lower than the plasma frequency. In the case of spatially periodic corrugation of the waveguide wall, the waves can be coupled, forming new waves with hybrid properties in a certain frequency range. The interaction of an electron beam with the hybrid waves differs from the interaction with a slow plasma wave in a waveguide with smooth walls or with the wave in an evacuated corrugated waveguide. For example, when two waves traveling in the same direction are coupled, the increments of the hybrid waves have values on the order of but somewhat smaller than those of the increment of a slow plasma wave in a smooth waveguide.Moscow Radio-Engineering Institute, Academy of Sciences of the USSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 34, No. 7, pp. 825–836, July, 1991.     

同轴膜片加载圆波导相对论行波管注-波互作用线性理论研究

 从改善圆盘加载波导作为相对论行波管慢波结构的特性入手，加入同轴内导体，着重研究其小信号理论。利用场匹配法导出了“热”色散方程并计算求解，具体分析了系统的电子注参量及慢波结构几何尺寸对小信号增益及慢波相速的影响,为同轴圆盘加载相对论行波管的设计提供了理论基础。     

Theoretical analysis of a relativistic travelling wave tube filled with plasma

A cold and uniform plasma-filled travelling wave tube with sinusoidally corrugated slow wave structure is driven by a finite thick annular intense relativistic electron beam with the entire system immersed in a strong longitudinal magnetic field. By means of the linear field theory, the dispersion relation for the relativistic travelling wave tube (RTWT) is derived. By numerical computation, the dispersion characteristics of the RTWT are analysed in different cases of various geometric parameters of the slow wave structure and plasma densities. Also the gain versus frequency for three different plasma densities and the peak gain of the tube versus plasma density are analysed. Some useful results are obtained on the basis of the discussion.     

Excitation of microwave by an annular electron beam in a plasma-filled dielectric lined waveguide

An axial relativistic electron beam passing through a slow wave structure is unstable to an electromagnetic perturbation whose phase velocity equals the velocity of the beam. This phenomenon of Cherenkov emission is the basis of all traveling wave tubes. In this paper an excitation of Cherenkov radiation by a thin annular relativistic electron beam in a plasma-filled dielectric-lined waveguide is analysed by use of the self-consistent linear theory. The effect of the thin annular electron beam on the beam-wave interaction is completely described by a jump condition. The dispersion equation and the simultaneous condition of the beam-wave interaction are derived. Finally, the growth rate of the wave is obtained, and the effect of the background plasma density and the electron beam radius on the growth rate of the wave are presented.This work is supported by National Natural Science Foundation of China.     

Study of Propagating Characteristics for Folded Waveguide TWT in Millimeter Wave

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.     

同轴交错圆盘加载波导慢波结构高频特性的研究

采用多导体传输线分析方法, 对同轴交错圆盘加载波导慢波结构进行了理论分析, 得到了这种慢波结构的色散方程; 利用该色散方程, 得到的色散特性与HFSS仿真软件模拟结果符合良好. 分析了结构参数的变化对同轴交错圆盘加载波导慢波结构的色散特性影响. 结果表明: 增加内径和减小慢波结构的单位周期长度可以拓展慢波结构的带宽. 对同轴圆盘加载波导和同轴交错圆盘加载波导两种慢波结构的色散特性进行了比较, 结果表明: 采用圆盘交错加载方式可以减弱色散, 拓展带宽. 研究结果对同轴交错圆盘加载波导在毫米波行波管中的应用具有指导意义. 关键词： 行波管 同轴交错圆盘加载波导 慢波结构 色散特性     

345 GHz微折叠波导慢波结构的粗糙度和加工垂直度

通过理论和数值模拟方法,考虑金属粗糙度的情况下,研究了加工垂直度公差角在0~6°范围内变化时折叠波导慢波结构的工作性能,结果表明:金属波导表面的粗糙度增大时,慢波结构中电磁信号的传输损耗增大;垂直度公差角的增大也使得电磁信号的传输损耗增加,而且垂直度公差角所引起的结构变化会引起器件的电压工作点漂移、带宽降低等。     

高效率超辐射相对论返波管

对新型同轴单程超辐射相对论返波管振荡器进行了进一步的研究。该振荡器的互作用区为同轴结构,外导体为一波纹波导,内导体为一光滑圆波导;辐射场从左端耦合到圆波导后输出,不需要截止颈。通过增加波纹周期数并调整互作用区末端波纹深度,器件的功率转换效率得到进一步的提高。当电子束电压为360 kV,电流为9.15 kA,外加磁场强度为2.7 T时,通过参数优化,模拟获得了瞬时峰值功率超过18 GW、脉冲宽度约400 ps,中心频率为8.1 GHz的微波输出,平均功率转换效率达到了275%。     

相对论行波管高频系统的数值模拟及实验验证

 分别采用有限元算法软件（HFSS）和有限积分法软件（MAFIA）对相对论行波管盘荷波导慢波结构进行建模，求出了相应的色散曲线。在此基础上设计了可用于相对论行波管的一种宽带和一种窄带的盘荷波导结构。加工了它们的冷测模型，测试曲线和模拟曲线吻合很好，从而验证了这两种软件尽管计算方法不同，但都可以对行波管慢波结构本征值问题进行求解。     

Coaxial Relativistic Backward Wave Oscillator and Coaxial Master Oscillator-Power Amplifier

A two and one half dimensional particle-in-cell code MAGIC has been used to investigate the nonlinear beam-wave interaction in a coaxial relativistic backward wave oscillator(RBWO) and optimize the dependence of the output power on electron beam nature parameter, slow wave structure geometry and magnetic guide field. The optimum conditions for the coaxial RBWO were obtained. The simulation results show: the coaxial RBWO can generate 3.2GW peak output power at 10.2GHz in the TM₀₂ made when an annular electron beam of 20KA is accelerated across a diode potential of 600KV and guided through a section of uniform coaxial corrugated waveguide by an axial magnetic field of 25KG, the peak efficiency is about 27% . A novel coaxial master oscillator–power amplifier was presented in this paper.     

毫米波静电聚焦行波管电子光学系统的设计

介绍了静电聚焦方式在毫米波行波管中的独特优势,分析了周期静电聚焦场的建立方法。基于某Ka波段行波管,首先根据指标要求设计了强流电子枪并选择类梳齿状结构作为其慢波电路,然后对电子枪和类梳齿状慢波电路组成的电子光学系统进行了模拟计算,最后对慢波电路的关键尺寸进行了容差分析。结果显示,在周期静电场的作用下,电子注全部平稳地通过了慢波系统。良好的静态通过率为后续高效率的注-波互作用奠定了基础,证明了利用静电场聚焦毫米波行波管中大电流密度电子注的可行性。     

毫米波行波管电子光学系统的设计

 利用基于虚边界元法的VBGUN程序和基于边界元法的MOM程序，对一折叠波导毫米波行波管的电子光学系统进行了设计。设计过程中使用计算相关性系数的方法调节参数，通过计算敏感性系数以考察加工误差带来的影响。设计过程显示：低导流系数、小束腰、高压缩比的毫米波电子枪的层流性与电极尺寸相关性很大，易受到加工误差的影响；聚束系统的设计难点在于轴上峰值磁感应强度要受到漂移管半径的限制，这一点可以通过提高工作电压和降低电流来平衡，因此它的设计必须与慢波结构的设计同时进行。     

W波段折叠波导行波管振荡抑制

为了抑制W波段折叠波导行波管研制中的自激振荡,保证行波管正常放大工作,分析了折叠波导慢波结构中反射振荡、返波振荡和带边振荡的产生原因,开展了折叠波导行波管振荡抑制技术研究,通过优化设计和工艺研究采用周期跳变作为关键技术用于W波段折叠波导行波管的研制。通过模拟检验和实验验证,证明采用了振荡抑制技术后行波管自激振荡得到了有效的抑制,W波段脉冲行波管在20%占空比时脉冲输出功率大于100 W,带宽大于5 GHz。     

On generation of electromagnetic waves in the terahertz frequency range in a multilayered open dielectric waveguide

We show that it is possible to produce terahertz wave generation in an open waveguide, which includes a multilayer dielectric plate. The plate consists of two dielectric layers with a corrugated interface. Electrons, drifting in the potential well, interact with the non-uniform electric field which is induced near the dielectric interface by the natural wave of the waveguide. The corrugated period and parameters of the electronic system are chosen in order to ensure the most effective interaction of electrons with a wave. Generation of electromagnetic waves is achieved by converting the electrons? energy into the electromagnetic wave energy.     

Optimum Design of a Ridge Waveguide Transformer for MMW Tube's

A ridge waveguide transformer is commonly used in output structure for millimeter wave tubes(such as magnetron and traveling wave tube). It is not satisfied, if a traditional designing method is used in broadband case. The optimum design of a ridge waveguide transformer is given in this paper. The computation results show that the reflect character of the transformer can be met the demands for broad band match.     

高功率微波器件中脉冲缩短现象的粒子模拟

脉冲缩短是高功率微波器件的一个普遍现象，它阻碍了输出微波能量的进一步提高，是高功率微波研究领域中急待解决的问题.以相对论返波管作为研究对象，运用粒子模拟的方法，研究了器件表面的爆炸发射、电子束电压和电流的脉动对输出微波性能的影响，从中得到了一些有益的结论，指出由强电场引起的慢波系统表面的爆炸发射是产生脉冲缩短的重要因素 ，电子束电流和束电压的脉动也会引起脉冲缩短，并提出了相应的克服方法. 关键词： 高功率微波器件 相对论返波管 脉冲缩短 粒子模拟