Review of the Novel Slow-Wave Structures for High-Power Traveling-Wave Tube

All-metal slow-wave structures are being paid great attention because of their advantages, such as good heat dissipation, high power capacity, wide passband, good wholeness of structure and large size etc. The emphases in this paper concentrate on the present state of study of four types of structures: helical groove, ring-plane, folded waveguide and periodically loaded waveguide, including theoretical analyses and practical applications. The problems and directions for future studies of these types of slow-wave circuits are also discussed. It is pointed out that all-metal slow-wave structures are suitable for applications in millimeter wave vacuum devices, like TWT, BWO, Gyro-TWT, and relativistic devices.     

金属覆盖介质波导在截止点附近的光学特性

本文提出一种适合于截止点附近计算含金属覆盖层介质波层的近似解析方法，详细；地讨论在截止点附近的光波导的模式传播特性 和光电调制特性，并结合有效折射率方法讨论了止型脊形波导调制器的截止条件。     

Cutoff Angles for the Group Velocity and Wave Vectors of a Backward Spin Wave in a Tangentially Magnetized Ferrite Slab

Based on an analysis of the dispersion relation for a backward spin wave in a tangentially magnetized ferrite slab, expressions are obtained that describe the cutoff angles of the wave and group velocity vectors for all modes of this wave.     

Theoretical and Experimental Study of a Compact Planar Slow-Wave Structure on a Dielectric Substrate for the W-Band Traveling-Wave Tube

Technical Physics - A miniature planar meander-type slow-wave structure (SWS) for a W-band traveling-wave tube is studied. Computer simulation of the SWS electrodynamic parameters is performed. A...     

Studies of a Gyrotron Traveling-Wave Tube with Helically Corrugated Waveguides at IAP Ras: Results and Prospects

Radiophysics and Quantum Electronics - The gyrotron traveling-wave tube (gyro-TWT) is a wideband version of gyrotron amplifiers, which produce pulsed or continuous-wave radiation in the...     

Propagation of a Surface Magnetoelastic Wave in a Ferromagnet Near the Orientation Phase Transition

Physics of the Solid State - The frequency dependences of the group velocity and the damping of a magnetoelastic surface wave have been studied at various values of an external magnetic field and...     

Study of Novel Slow Wave Circuit for Miniaturized Millimeter Wave Helical Traveling Wave Tube

Two kinds of novel helical slow wave circuit, supported by Chemical Vapor Deposition (CVD) diamond, are presented. They are applying in miniaturized millimeter wave helical traveling wave tube. Cold test characteristic of these circuits are simulated by MAFIA code. Higher performances are achieved with smaller size, compared with conventional circuit supported by BeO rods. The nonlinear analysis is implemented by Beam and Wave Interaction (BWI) module, which is a part of TWTCAD Integrated Framework. Results have been found to be consistent with the expectation. It should be wider apply in microwave and millimeter wave vacuum electronic devices.     

Colliding Wave Solutions in a Symmetric Non-Metric Theory

A method is given to generate the non-linear interaction (collision) of linearly polarized gravity coupled torsion waves in a non-metric theory. Explicit examples are given in which strong mutual focussing of gravitational waves containing impulsive and shock components coupled with torsion waves does not result in a curvature singularity. However, the collision of purely torsion waves displays a curvature singularity in the region of interaction.     

氢氧爆轰波在激波管中的成长机制研究

 针对气相爆轰波成长机制研究,采用压力传感器和高速摄影技术,测试了氢氧混合气体在点火后的火焰波、前驱冲击波以及爆轰波的成长变化过程,计算了冲击波过程参数和气体状态参数,分析了火焰加速机制。实验结果表明,APX-RS型高速摄影系统可用于拍摄气相爆轰波的成长历程;氢氧爆轰波的产生是由于湍流火焰和冲击波的相互正反馈作用,导致反应区内多处发生局部爆炸,爆炸波与冲击波相互耦合,最终成长为定常爆轰波。     

脉管制冷与气波制冷耦合的研究

介绍了一种耦合脉管制冷与气波制冷技术的新型制冷机脉管式气波制冷机。分析了脉管式气波制冷机的制冷原理 ,对脉管制冷与气波制冷的耦合性进行了试验研究。同时 ,对振荡管长度、气体分配器的转速等影响脉管式气波制冷机性能的因素进行了试验。通过研究 ,获得了一些有益的结论 ,并给出了各种因素对制冷机等熵效率的影响曲线     

Calculation of the Parameters for Ring-loop Traveling Wave Tube in MMW

The feature of the ring-loop slow wave structure is high coupling impedance and low harmonic wave components. Therefore ring-loop traveling wave tube (TWT) has advantages of high gain, small dimension, higher operating voltage and less danger of the backward wave oscillation. But calculation of the ring-loop is rather difficult. Here on basis of calculation of dispersion and impedance, a fast estimation of interaction efficiency, output power and saturated gain for Ka-band ring-loop TWT are given.     

Ka波段耦合腔行波管放大器设计

由于Ka波段耦合腔行波管放大器设计技术取得了较大的发展,已经可以满足军用雷达的严格要求,这种设计技术也受到更多的关注.这里简要介绍Ka波段耦合腔行波管放大器的设计技术.通过介绍Ka波段耦合腔行波管放大器的基本组成、工作原理及设计中仿真工具的运用来说明这种设计技术.用这种设计技术成功设计出了多种耦合腔行波管放大器,在功率和体积方面突破了原有的Ka波段固态和螺旋线行波管放大器的局限,取得了明显的进步.Ka波段耦合腔行波管放大器的设计技术经过实践验证,在输出功率、带宽及重量方面已经取得了重大突破,满足了现代军用雷达的需求.     

Linear Analysis of Folded Double-Ridged Waveguide Slow-Wave Structure for Millimeter Wave Traveling Wave Tube

A novel slow-wave structure （SWS）, the folded double-ridged waveguide structure, is presented and its linear gain properties are investigated. The perturbed dispersion equation is derived and the small signal growth rate is caleulated for dimensions of the ridge-loaded region and the parameters of the electron beam. The novel structure has potential applications in the production of high power and broad band radiation. For a cold beam, the linear theory predicts a gain of 1.1-1.27dB/period and a 3-dB small-signal gain bandwidth of 30% in W-band. A comparison between the folded double-ridged waveguide SWS and folded waveguide SWS （FWSWS） shows that with the same physical parameters, the novel SWS has an advantage over the FWSWS on the bandwidth and electron efficiency.     

Nonlinear Theory of the Plasma Wave Excitation in a Bounded Beam-Plasma System

The excitation of symmetric and antisymmetric plasma waves by a beam layer that moves within a homogeneous plasma enclosed by a metallic wall was dealt with theoretically. Investigations were carried out for the magnetic field free case and for a magnetized electron beam. In the latter case, the beam electrons are assumed to be unable to move in the perpendicular direction. The theoretical model bases upon an extension of the well known single wave theory to a two-dimensional beam-plasma system. Special emphasis should be paid to the fact that the perpendicular wave profile of the excited waves was determined self-consistently. Energy and momentum balance equations are derived for this system. The theoretical method outlined in this paper which is based on a Green's-function technique can be extended easily to three-dimensional systems or to beam-plasma systems with other boundary conditions. The main features of the saturation process of the basic unstable wave types are discussed. Several interesting effects were found in the magnetic field free case: (i) numerical solutions describe an increasing steepening of the wave amplitudes in perpendicular direction near the center of the system for the symmetric potential wave; (ii) for the antisymmetric wave, a smoothing tendency was found in the development of the perpendicular wave potential profile; (iii) spatial separation of the slow and fast beam electrons was observed; (iv) it is shown for the antisymmetric potential wave type that, under certain conditions, a very efficient beam particle retardation mechanism occurs which is connected with a strong reduction of the formation of a fast particle group; (v) generally it was shown that the conversion of the kinetic energy of the beam electrons into the plasma wave energy may be more effective as compared with the case of the magnetized beam.     

Numerical Perspective of Second-Harmonic Generation of Circumferential Guided Wave Propagation in a Circular Tube

The effect of second-harmonic generation(SHG) by primary(fundamental) circumferential guided wave(CGW)propagation is investigated from a numerical standpoint.To enable that the second harmonic of the primary CGW mode can accumulate along the circumferential direction,an appropriate mode pair of primary and double frequency CGWs is chosen.Finite element simulations and evaluations of nonlinear CGW propagation are analyzed for the selected CGW mode pair.The numerical simulations performed directly demonstrate that the response of SHG is completely generated by the desired primary CGW mode that satisfies the condition of phase velocity matching at a specific driving frequency,and that the second harmonic of the primary CGW mode does have a cumulative effect with circumferential angles.The numerical perspective obtained yields an insight into the complicated physical process of SHG of primary CGW propagation unavailable previously.     

关于改进型脉管制冷机原理的几种分析模式

简要叙述了改进型脉管制冷机的发展背景 ,结构的改进同时推动了理论的进步 ,目前对改进型脉管制冷机的热力学原理和制冷量的计算有多种理论模式。文中分别对主要的几种模式进行简要的叙述 ,分析其优点及不足之处 ,希望对于理论的进一步完善有一定的借鉴之处 ,同时也希望能够促进结构的进一步优化     

Numerical Evaluation of a Two-Loop Diagram in the Cutoff Regularization

The sunset diagram of λφ4 theory is evaluated numerically in cutoff scheme and a nonzero finite term(in accordance with dimensional regularization (DR) result) is found in contrast to published calculations. This findingdramatically reduces the critical couplings for symmetry breaking in the two-loop effective potential discussed in ourprevious work.     

Numerical Evaluation of a Two-Loop Diagram in the Cutoff Regularization

The sunset diagram of λΦ^4 theory is evaluated numerically in cutoff scheme and a nonzero finite term (in accordance with dimensional regularization (DR) result) is found in contrast to published calculations. This finding dramatically reduces the critical couplings for symmetry breaking in the two-loop effective potential discussed in our previous work.