The autoresonant peniotron with a quadrupole interaction circuit

In the autoresonant peniotron interaction, all of the electrons will be able to give almost all of their kinetic energy to an electromagnetic wave, resulting in a conversion efficiency of nearly 100%, if the condition of V_p=C is satisfied in an interaction circuit and the initial velocity ratio of electrons is correctly given as a function of the electron kinetic energy. A quadrupole circuit is proposed in which the above circuit condition is usually satisfied and the RF electric field distribution in a cross section is suitable for the peniotron interaction at the fundamental cyclotron frequency. The design procedure for the test tube with the circuit and some simulation results concerned with the tube's operation are described     

外场作用双导线的电磁耦合时域分析方法

基于时域有限差分（finite-difference time-domain，FDTD）法和传输线方程，并结合插值技术，研究了一种高效的时域混合算法，能够快速模拟电磁波照射自由空间和屏蔽腔内双导体传输线的电磁耦合，并实现空间电磁场与双导线瞬态响应的同步计算.该算法先采用FDTD方法模拟双导线周围空间的电磁场分布，结合插值技术构建适用于双导线电磁耦合的传输线方程，再采用FDTD的中心差分格式进行离散，从而求解得到传输线和端接负载上的瞬态响应.同时，分析双导线间距对其电磁耦合的影响，掌握其耦合规律.通过相应数值算例的模拟，并与FDTD方法进行对比，验证了该时域混合算法的正确性和高效性.     

电磁脉冲通过孔缝到系统内部的耦合约束

介绍了核电磁脉冲通过孔缝耦合到系统内部的最大能量计算方法，给出了倒指数型电磁脉冲最大耦合能量的解析表达式。该模型在定孔总截面正比于波频率4次方时，计算出通过孔耦合到腔体内部的最大能量，实现电磁耦合能量的计算。倒指数脉冲模型的理论计算结果，可以对电子设备电磁脉冲的保护具有重要意义。     

Theoretical analysis of gyrotron amplifier with undulated waveguide

In this paper the interaction between a relativistic electron beam moving in a static magnetic field and a travelling electromagnetic wave is analysed by using the kinetic power theorem. The concept of the electron bunching function is introduced to illustrate the bunching process of beam electrons as a whole. By numerical calculation, the energy exchange process between gyrating electrons and the travelling wave field is obtained in detail. The results of the calculation show that the imaginary part of the axial wave number does not stay constant along the interaction length and that the gain characteristic is non-linear. Based on this analytic method, the maximum output power and efficiency of the gyrotron amplifier with a uniform waveguide are calculated and are found to depend critically on the value of the static magnetic field and the operating frequency. A new type of gyrotron amplifier is suggested here. In this device the gyrating electrons interact with the travelling wave in an undulated waveguide. Its instantaneous bandwidth is somewhat broadened and the optimum value of applied magnetic field is not too critical.     

Efficient broadband excitation of the n = 0 surface magnetostatic waves in a y.i.g. slab

This letter describes an efficient method for exciting the lowest-order surface magnetostatic wave in a transversely magnetised single-crystal y.i.g. slab. The total coupling loss from an electromagnetic wave to a surface magnetostatic wave and back into an electromagnetic wave is measured to be less than 2.5dB, from 3.2 to 3.8GHz. The propagation characteristic of the surface magnetosatic wave is also discussed.     

Particle Simulation of a 35-GHz Third-Harmonic Low-Voltage Complex Cavity Gyrotron

A self-consistent particle simulation code has been developed for the research of a 35-GHz third-harmonic Low-voltage complex cavity gyrotron. Aided with microcomputer we use FORTRAN to simulate the process of interaction between electron beam and electromagnetic field. About 7000 macro particles are included at the same time. In the program many useful physical graphs are accessible for the further research of this kind of gyrotron such as the field profile, electrons distribution in various spaces, output power, efficiency and et al. Such simulation results may be helpful to the optimization of devices operation parameters     

基于时频分析的电磁脉冲耦合效应研究*

为了解高功率电磁脉冲对电子系统的干扰与毁伤影响,利用基于Wigner鄄Ville 分布的时频分析方法对耦合进电子系统内部的电磁信号进行了特征分析。与单独的时域分析和频域分析相比,时频分析不仅能够得到信号的时域特征和频域特征,还能同时得到信号各频率分量随时间的变化情况。利用瞬态极化时频分析,进一步得到信号极化状态在时频域的分布。仿真结果表明,时频分析得到的结果更全面详细,可以根据时频分析得到的信号特征更加准确地指导电子系统的高功率电磁脉冲防护加固。     

Electromagnetic wave effects on microwave transistors using afull-wave time-domain model

A detailed full-wave time-domain simulation model for the analysis of electromagnetic effects on the behavior of the submicrometer-gate field-effect transistor (FET's) is presented. The full wave simulation model couples a three-dimensional (3-D) time-domain solution of Maxwell's equations to the active device model. The active device model is based on the moments of the Boltzmann's transport equation obtained by integration over the momentum space. The coupling between the two models is established by using fields obtained from the solution of Maxwell's equations in the active device model to calculate the current densities inside the device. These current densities are used to update the electric and magnetic fields. Numerical results are generated using the coupled model to investigate the effects of electron-wave interaction on the behavior of microwave FET's. The results show that the voltage gain increases along the device width. While the amplitude of the input-voltage wave decays along the device width, due to the electromagnetic energy loss to the conducting electrons, the amplitude of the output-voltage wave increases as more and more energy is transferred from the electrons to the propagating wave along the device width. The simulation confirms that there is an optimum device width for highest voltage gain for a given device structure. Fourier analysis is performed on the device output characteristics to obtain the gain-frequency and phase-frequency dependencies. The analysis shows a nonlinear energy build-up and wave dispersion at higher frequencies     

Stimulated Brillouin scattering as a parametric interaction

In the stimulated Brillouin scattering of an intense laser beam, a forward-traveling coherent acoustic wave and a backward-traveling electromagnetic wave are produced. This interaction is studied from the coupled mode approach and shown to be describable as a parametric interaction. An inherent instability of this particular interaction is discussed. Frequencies of the interacting waves are calculated for quartz and cadmium sulfide. The non-linearity is shown to be due to the electrostrictive and photoelastic properties of the medium. By expressing the coupling coefficient as a tensor of rank four, selection rules for the interaction in isotropic and certain anisotropic media are derived. Finally the experimental approach for detection of the acoustic wave is discussed.     

Modeling and Measurement of Interlevel Electromagnetic Coupling and Fringing Effect in a Hierarchical Power Distribution Network Using Segmentation Method With Resonant Cavity Model

A hierarchical power distribution network (PDN) consists of chip, package, and printed circuit board (PCB) level PDNs, as well as various structures such as via, ball, and wire bond interconnections, which connect the different level PDNs. When estimating the simultaneous switching noise (SSN) generation and evaluating PDN designs, PDN impedance calculation is an efficient criterion. In this paper, we introduce two new kinds of modeling approaches that are exceptionally suited to improving the accuracy of the PDN impedance estimation, especially for hierarchical PDN. First, we propose a modeling procedure to add an interlevel electromagnetic coupling effect between PDNs of different levels, based on the resonant cavity model and segmentation method. In order to effectively consider the interlevel electromagnetic coupling effect, we introduce a new concept of interlevel PDN, which is, for example, composed of a metal plate in the package-level PDN and a metal plate in the PCB-level PDN. Next, we present a modeling procedure to include the fringing field effect at the edge of small-size PDN structure, which causes a considerable shift of cavity resonance frequencies in the PDN impedance profile. In order to verify the proposed modeling approaches, we have fabricated a series of test vehicles by combining two package-level PDN designs with a PCB-level PDN design. Finally, we have successfully validated the proposed modeling approaches with a series of frequency-domain measurements in a frequency range up to 5 GHz.      

Illumination d’un réseau de lignes ou de câbles par une onde de foudre Modélisation par des générateurs de courant

In this paper we propose a new formalism for the analysis of electromagnetic coupling between the lightning wave and a network of lines or cables. This approach allows obtaining currents and induced voltages directly on the set of lines or cables extremities. For this objective we use the current generators representation of the lightning wave. Then by a mathematical formulation based on the topological analysis of the network, we deduce a linear equation system which resolution leads directly to the currents and induced voltages. In order to confirm our theoretical work, we present a set of applications that allows validating this formalism.     

A simplified approach to modeling the interaction between grounding grid and lightning stroke

In this work, a new approach for the modeling of the interaction between grounding grid and lightning stroke is described. We treat the case of direct and indirect effects of lightning strike. In the case of direct impact, we inject in point of grounding system a current with bi-exponential wave shape and we calculate the distribution of potentials and currents on the grid and the electromagnetic field it will emit. For the second case, we treat a problem of electromagnetic coupling, which is to calculate the induced currents that developed on the grounding grid when this later is illuminated by a lightning channel located in its vicinity. The presented model is validated by comparing the obtained results to the results arising from the full wave (antenna) model available in literature and to the results obtained by using NEC4 software. The principal advantage of the presented approach is the simplicity of the implementation providing a direct determination of the both current and potential distribution along the grounding grid and the related electromagnetic field in an arbitrary point in the air and/or soil, as well.     

瞬态电磁波对电子设备电缆的电磁耦合分析

瞬态电磁波对电子设备电缆的电磁耦合预测分析,是电子设备的电磁兼容性预测与分析的重要方面。提出了电磁场对电缆的电磁耦合模型,介绍了电磁耦合的数学计算公式,并对3种瞬态电磁脉冲对电缆的电磁耦合进行了预测分析,数值分析结果对有效抑制和减小电磁波对电缆的电磁干扰有一定的参考价值和指导意义。     

Fast Convergence Algorithm for Earthquake Prediction Using SLF/ELF Horizontal Electric Dipole during Day and Night and Schumann Resonance

Electromagnetic wave radiation from a SLF/ELF horizontal electric dipole (HED) related to seismic activity is discussed. In order to estimate the effects on the electromagnetic waves associated with the seismic activity, SLF/ELF waves on the ground radiated from a possible seismic current source modeled as a electric dipole, are precisely computed by using a speeding numerical convergence algorithm. A theoretical calculation of the VLF/SLF electric wave propagating among the Earth-ionosphere cavity generally utilizes the full wave method to solve the model equation. The field in the cavity is comprehended as the sum of each wave mode. However, this method is very complex, and unsuitable to the ELF frequency band. In 1999, Barrick proposed an algorithm, which was only suitable to solve the electromagnetic problems under the ideal electric conductor condition. To solve the problems under the non-ideal electric conductor condition, we have further developed Barrick??s method and proposed a speeding numerical convergence algorithm. The spherical harmonic series expressions of electromagnetic fields excited by SLF/ELF HED in non-ideal Earth-ionosphere cavity are derived. The speed of this algorithm is faster thirty times than it of calculating directly the sum of the series. If it calculates directly the sum of the series, it needs 1,000 series items, while it needs only 200 series items by this algorithm. Our algorithm is compared with the second order spherical surface approximate algorithm, and two algorithms agree with each other very well. Therefore, our algorithm is correct. Schumann resonance is also verified.     

A novel numerical synthetic technique for determination of the TMon dispersion relation in a coaxial corrugated cylindrical waveguide

A novel, highly accurate numerical synthetic technique for determining the complete dispersive characteristics of electromagnetic modes in a spatially periodic structure is presented. The numerical method based on the coupling of the finite difference method in time domain with the discrete fourier transform is applied to calculate the eigenfrequencies and eigenfield distribution of a resonant cavity which is an appropriately shorted periodic slow wave circuit of N periods at both ends. The analytical synthetic technique, which is based on the intrinsic characteristic of spatially periodic structure, is used to derive the complete dispersion relation using the numerically measured resonances. The method was successfully applied for the case of TM_on modes in a coaxial corrugated waveguide and is applicable to slow wave structures of arbitrary geometry.     

Embedded metal mask enhanced evanescent near field optical lithography

Simulation of evanescent optical lithography using an embedded metal mask (EMM) shows that resolution and throughput are significantly enhanced over conventional ENFOL, due to coupling between surface plasmons and cavity mode excitations. The key role played by surface plasmon polaritons and the effects of wave vector matching between the incoming photon and the EMM mask grating are clear from the simulation. In particular a double peaked resonant intensity distribution is revealed for the first time within the dielectric filled mask cavity, for the shorter wavelengths only. This effect is highly conducive to efficient sub wavelength lithography and has not been discovered by previous simulations. The EMM–ENFOL process has considerable potential for cheap, high throughput nanolithography with resolution well below diffraction limits.     

Plasmonic Modulation of Valleytronic Emission in Two-Dimensional Transition Metal Dichalcogenides

Monolayered transition metal dichalcogenides (TMDs) are one kind of hexagonal 2D semiconductors with a direct bandgap structure. Due to the property of natural broken inversion symmetry in the lattice, the strong spin–orbit coupling of electrons in TMDs can induce degenerate levels with antiparallel spins in K and K′ valleys, which selectively respond with external light excitations. Surface plasmon resonance with efficient electromagnetic enhancement and near-field coupling provides excellent potential opportunities to modulate valley emission of TMDs. Efforts have been devoted to investigating the interaction principles and applications of this research field. This review focuses on plasmonic modulation of valleytronic emission in TMDs with surface plasmon polaritons (SPP) and localized surface plasmons (LSP) based on different modulation principles, respectively, and discusses possible research directions for future device applications.     

Transmission Properties of Radar Wave through Reentry Plasma Sheath

In this paper,by taking into account the coupling of the ionization of ablation gas and atmosphere,an electrons density distribution model is built. Using this model,the transmission properties of different polarization radar wave through sheath are evaluated on the basis of the transmission matrix theory. Then,we discuss the effects of the electrons density,the added magnetic field,and the radar wave frequency on the transmission properties. As a result of this investigation,greater transmission power could be gained in order to efficiently shorten communication blackout,by reducing the electrons density or choosing proper added magnetic field and the frequency of the radar wave according to the different polarization form of the radar wave.     

金属腔体多耦合通道电磁特性研究

实际金属腔体常开有多个通道,使得腔内电磁环境变得复杂。以分析腔体多通道耦合电磁特性为出发点,建立平面波入射下矩形、圆柱腔体实例模型,引入对比系数作为评价手段,侧重研究孔缝、贯穿线缆两种耦合通道对腔内电磁场的影响,寻求共性规律。结果表明:腔外线缆长度变化不影响谐振点出现位置,随长度增加腔体屏蔽效能(SE)下降;腔内线缆随长度增加,谐振频率降低,两腔体具有如上共性结论。基于给定的模型及参数设定,通过比较系数可判断矩形腔体450 MHz 之前线缆耦合为主;贯穿线较长时, 510 MHz 之前圆柱腔体线缆耦合为主;贯穿线较短时,两个局部频点之外的其它频段孔缝耦合为主;涂覆磁损耗型吸波材料提升腔体SE 效果最好,且SE越低,提升效果越明显。