Fast measurement and prediction method for electromagnetic susceptibility of receiver

Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional two-tone test.Firstly,two signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent analysis.Secondly,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the power domain,which provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the receiver.An experiment performed on a radar receiver confirms the reliability of the method proposed in this paper.It shows that the interference of each harmonic frequency and each order to the receiver can be identified and predicted with the sensitivity model.Based on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized.

Finite element solution based on fast numerical technique for large-scale electromagnetic computation

A numerical technique of the target-region locating （TRL） solver in conjunction with the wave-front method is presented for the application of the finite element method （FEM） for 3-D electromagnetic computation. First, the principle of TRL technique is described. Then, the availability of TRL solver for nonlinear application is particularly discussed demonstrating that this solver can be easily used while still remaining great efficiency. The implementation on how to apply this technique in FEM based on magnetic vector potential （MVP） is also introduced. Finally, a numerical example of 3-D magnetostatic modeling using the TRL solver and FEMLAB is given. It shows that a huge computer resource can be saved by employing the new solver.

Parallel Iterative FEM Solver with Initial Guess for Frequency Domain Electromagnetic Analysis

The finite element method is a key player in computational electromag-netics for designing RF(Radio Frequency)components such as waveguides.The frequency-domain analysis is fundamental to identify the characteristics of the components.For the conventional frequency-domain electromagnetic analysis using FEM(Finite Element Method),the system matrix is complex-numbered as well as indefinite.The iterative solvers can be faster than the direct solver when the solver convergence is guaranteed and done in a few steps.However,such complex-numbered and indefinite systems are hard to exploit the merit of the iterative solver.It is also hard to benefit from matrix factorization techniques due to varying system matrix parts according to frequency.Overall,it is hard to adopt conventional iterative solvers even though the system matrix is sparse.A new parallel iterative FEM solver for frequency domain analysis is implemented for inhomogeneous waveguide structures in this paper.In this implementation,the previous solution of the iterative solver of Matlab(Matrix Laboratory)employ-ing the preconditioner is used for the initial guess for the next step’s solution process.The overlapped parallel stage using Matlab’s Parallel Computing Toolbox is also proposed to alleviate the cold starting,which ruins the convergence of early steps in each parallel stage.Numerical experiments based on waveguide structures have demonstrated the accuracy and efficiency of the proposed scheme.

Modeling the Physical Parameters of Solenoids for MEMS Applications

The paper is devoted to study of the electrical parameters of the motion parts of the MEMS such as solenoids. The analytical background is given in order to describe the influence of the electrical field components on the forces, which are result of interaction of the electromagnetic (EM) field components with the parts of motion devices of MEMS. The given analytical formulas open the ability to calculate the self-inductance of the microsolenoids of the different kind, as well as the stored energy of such motion devices, that could be used for the modeling and optimization of parameters of running devices of MEMS such as actuators, sensors etc.

EMS型中低速磁浮列车悬浮架技术研究综述

悬浮架是承载EMS(electro-magnetic suspension)型中低速磁浮列车运行的关键子系统,影响列车的悬浮稳定性、舒适性和安全性,需要对其进行深入研究.围绕国内外EMS型中低速磁浮列车应用案例,介绍了(悬挂)端置式悬浮架、(悬挂)中置式悬浮架的技术方案和特征,总结了主要技术指标.结合悬浮架技术研究、发展现状,讨论了磁轨作用关系、运动解耦能力、动力学性能、结构强度以及悬浮冗余设计五大研究方向,通过对研究内容梳理和总结,归纳了现有前沿科学问题和工程技术挑战:一是轨距亟须统一;二是动态磁轨关系研究欠缺;三是悬浮架横向动力学有待研究;四是悬浮架疲劳强度分析及试验不足;五是悬浮架机械结构冗余设计方案较少.

Mathematical Wave Functions and 3D Finite Element Modelling of the Electron and Positron

The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles.

Spatio-Temporal Changes of Soil Salinity in Arid Areas of South Xinjiang Using Electromagnetic Induction

The aim of this paper was to research the spatio-temporal changes in total soluble salt content （TS） in a typical arid region of South Xinjiang, China, where the climate is arid and soil salinization happens easily. The total soluble salt content was interpreted by measurements made in the horizontal mode with EM38 and EM31. The electromagnetic induction （EM） surveys were made three times with the apparent soil electrical conductivity （ECa） measurements taken at 3 873 locations in Nov. 2008, 4 807 locations in Apr. 2009 and 6 324 locations in Nov. 2009, respectively. For interpreting the ECa measurements into total soluble salt content, calibtion sites were needed for EM survey of each time, e.g., 66 sites were selected in Nov. 2008 to measure ECa, and soils-core samples were taken by different depth layers of 0-10, 10-20 and 20-40 cm at the same time. On every time duplicate samples were taken at five sites to allevaite the local-scale variability, and soil temperatures in different layers through the profiles were also measured. Factors including TS, pH, water content, bulk density were analyzed by lab experiments. ECa calibration equations were obtained by linear regression analysis, which indicated that soil salinity was one primary concern to ECa with a determination coefficient of 0.792 in 0-10 cm layer, 0.711 in 10-20 cm layer and 0.544 in 20-40 cm layer, respectively. The maps of spatial distribution were predicted by Kriging interpolation, which showed that the high soil salinity was located near the drainage canal, which validated the trend effect caused by the irrigation canal and the drainage canal. And by comparing the soil salinity in different layers, the soluble salt accumulated to the top soil surface only in the area where the soil salinization was serious, and in the other areas, the soil salinity trended to increase from the top soil surface to 40 cm depth. Temporal changes showed that the soil salinity in November was higher than that in April, and the soil salinization trended to aggravate, especially in the top soil layer of 0-10 cm.

Study of electromagnetic and acoustic emission in creep experiments of water-containing rock samples

Based on biaxial shear creep tests conducted on rock samples with different water contents, we present the results of our study on the regularities of electromagnetic and acoustic emission during the process of creep experiments in which we have analyzed the contribution of water to the occurrence of electromagnetic radiation. The result shows that in the creep-fracturing course of rock samples, when the water content increases, the initial frequency and amplitude of electromagnetic and acoustic emission also increases, but at a decreasing growth rate caused by loading stress. This can be used as a criterion for the long-term stability of rock masses under conditions of repeated inundation and discharge of water.

Numerical Method for Solving Electromagnetic Scattering Problem by Many Small Impedance Bodies

In this paper, we study electromagnetic (EM) wave scattering problem by many small impedance bodies. A numerical method for solving this problem is presented. The problem is solved under the physical assumptions ka??1, where a is the characteristic size of the bodies and k is the wave number. This problem is solved asymptotically and numerical experiments are provided to illustrate the idea of the method. Error estimate for the asymptotic solution is also discussed.

Guided and Direct Wave Evaluation of Controlled Source Electromagnetic Survey Using Finite Element Method

Deep target hydrocarbon detection is still challenging and expensive. Direct hydrocarbon indicators (DHIs) in seismic data do not correspond to economical hydrocarbon exploration. Due to unreliability in seismic data for the detection of DHIs, new methods have been investigated. Marine controlled source electromagnet (MCSEM) or Sea bed logging (SBL) is new method for the detection of deep target hydrocarbon reservoir. Sea bed logging has also the potential to reduce the risks of DHIs in deep sea environment. Modelling of real sea environment helps to reduce the further risks before drilling the oil wells. 3D electromagnetic (EM) modelling of seabed logging requires more accurate methods for the detection of hydrocarbon reservoir. Finite element method (FEM) is chosen for the modelling of seabed logging to get more precise EM response from hydrocarbon reservoir below 4000 m from seabed. FEM allows to investigate the total electric and magnetic fields instead of scattered electric and magnetic fields, which shows accurate and precise resistivity contrast below the seabed. From the modelling results, It was investigated that Hz field shows higher magni- tude with 342% than the Ex field. It was observed that 0.125 Hz frequency can be able to show better resistivity contrast of Hz field (31.30%) and Ex field (16.49%) at target depth of 1000 m below seafloor for our proposed model. Hz and Ex field delineation was found to decrease as target depth increased from 1000 m to 4000 m. At the target depth of 4000 m, no field delineation response was seen from the current electromagnetic (EM) antenna used by the industry. New EM antenna has been used to see the EM response for deep target hydrocarbon detection. It was investigated that novel EM antenna shows better delineation at 4000 m target depth for Ex and Hz field up to 10.3% and 15.1% respectively. Novel EM antenna also shows better Hz phase response (128.4%) than the Ex phase response (38.3%) at the target depth of 4000 m below the seafloor.

A Preliminary Ray Tracing Approach to Computational Electromagnetics for Reverberation Chambers

This paper summarizes a theoretical design analysis for the implementation of an electromagnetic modeling tool, focusing on the simulation of electromagnetic field propagation inside reverberation chambers. The simulation algorithms which have been developed rely on a ray tracing technique, adapted in such a way as to maximize compatibility with the specific requirements and parameters, as applicable for reverberation chambers. The most significant example of a typical parameter is the high rate of wave reflections inside the chambers’ cavity. An implementation of the algorithms was used for simulation of several theoretically predictable cases. Study of the results of these test cases showed that some of the design decisions and algorithms used need to be reviewed in order to optimize the computational aspects of the application, such as resource management (memory, CPU time). Results of typical sample cases are re- viewed in this paper as well, in order to identify possible pitfalls and objectives for future research.

Semisolid slurry of 7A04 aluminum alloy prepared by electromagnetic stirring and Sc, Zr additions

Slurry preparation is one of the most critical steps for semisolid casting, and its primary goal is to prepare slurry with uniformly distributed fine globules. In this work, electromagnetic stirring(EMS) and the addition of Sc and Zr elements were used to prepare semisolid slurry of 7A04 aluminum alloy in a large diameter slurry maker. The effects of different treatments on the microstructure, composition and their radial homogeneity were investigated. The results show that, compared to the slurry without any treatment, large volume slurry with finer and more uniform microstructure can be obtained when treated by EMS, Sc, or Zr additions individually. EMS is more competent in the microstructural and chemical homogenization of the slurry while Sc and Zr additions are more excellent in its microstructural refinement. The combined treatment of EMS, Sc and Zr produces premium 7A04 aluminum alloy slurry with uniformly distributed fine α-Al globules and composition. The interaction mechanism between EMS and Sc and Zr additions was also discussed.

COMPUTER SIMULATION OF CONTINUOUS ELECTROMAGNETIC STIRRING FOR MAKING RHEOLOGIC SEMI-SOLID SLURRY OF ZL112Y ALUMINUM ALLOY

To realize the technology of fabricating the rheologic semi-solid slurry of ZL112Y aluminum alloy via continues electromagnetic stirring process, ANSYS software was used to simulate electromagnetic force field and fluid velocity field in the alloy melt in a crucible tube in three coils. In the first section of the paper, eletromagnetic force field and fluid velocity field caused by single coil were simulated. The result of this simulation gives an average velocity of 3.2 cm/s and it is called critical velocity because a fluid velocity over it will cause a fine and spherical structure of solid primary a in a semi-solid melt. And, from this result, a reasonable temperature of semi-solid of the alloy and an electrical current intensity were established. The electrical current intensity of the result of this simulation corresponded to the current intensity used in a practice experiment, in which the primary α was obviously refined and sphericized. Based on this simulation of single coil electromagnetic stirring, in the second section of the paper, eletromagnetic force field and fluid velocity field caused by three coils were simulated. The result of the simulation shows that, 1） there is a semi-solid zone of 32 mm from bottom of the crucible tube to the upper; 2） the electrical current intensities of three coils of 400 A, 600 A, and 400 A, which were set to top range, middle range and bottom range of the tube, respectively, were the optimum parameters of electromagnetic current intensity under the condition of this investigation; and 3） under effect of these electromagnetic current intensity, the fluid velocities of the melt in the tube were 6.3 cm/s in top range, 3.75 cm/s in middle range, and 3.9 cm/s in bottom range of it, respectively.

Progress of Expert Systems in Electromagnetic Engineering

It is urgent to solve various problems in electromagnetic （EM） engineering under the increasingly complicated environment. Some expert systems （ES） come into being just to keep up with the demand for solving these problems. Combined with the analysis of development orES technology and the development trend of EM engineering software in recent years, the application orES technology in EM engineering is discussed, and especially the progress of complete ES in electromagnetic compatible （EMC） is introduced.

A nonlinear control method for the electromagnetic suspension system of the maglev train

To deal with the inherent nonlinearity and open-loop instability of the electromagnetic suspension（EMS） system,a new nonlinear control method is proposed.The simulation results show that,for a PID controller,the over-shoot of the system response to an airgap step disturbance is about 3 mm,and the transient time is 6 s;however,for the proposed nonlinear controller,there is no overshoot and transient time within 2 s.The proposed method has a faster response and stronger robustness.With a designed bi-DSP suspension controller,this nonlinear control method was implemented on the Shanghai Urban Maglev Test Line（SUMTL） to validate its effectiveness and feasibility.

EFFICIENT COMPUTATIONAL METHOD FOR TRANSIENT EM RESPONSE OF LARGE-LOOP SOURCE OVER LAYERED EARTH

Calculations of the ElectroMagnetic(EM) response produced by a large horizontal loop placed over layered medium are rather complex because its integral expression contains the product of two Bessel functions and has a divergent term. In this paper, an improved fast Hankel and Gaver-Stehfest transforms are introduced to solve the strong-oscillation and slow-decay properties of the integrand, where one Bessel function in the product is substituted by a carefully chosen polynomial of high accuracy and the other used as the digital filter coefficients in the convolution integral. Comparisons prove the validity and the efficiency of the proposed method.

EMS型磁浮列车悬浮静磁场电磁环境仿真研究

为量化评估常导电磁悬浮(EMS)型磁浮列车的电磁环境风险,在确定位于磁浮列车悬浮架两侧的直线电机转子励磁线圈为辐射源的基础上,采用有限元软件COMSOL Multiphysics,建立长定子轨道和EMS型磁浮列车三维结构模型,对直线电机的悬浮电磁特性以及它在周围空间和磁浮列车车厢内产生的静磁场进行仿真计算,并将车厢内的磁通密度计算结果与静磁场暴露限值标准进行对比。结果表明:长定子直线电机在励磁电流为25 A时,悬浮间隙中心线处磁通密度最大模值约为0.9 T,悬浮电磁力约为19.7 kN·m^(-1);磁浮列车夹层位置处磁通密度最大模值在9.39~53.6 uT范围内,车厢内磁通密度最大模值约为6.93 uT;悬浮励磁线圈在车厢内产生的磁通密度最大值远低于国际非电离辐射防护委员会(ICNIRP)对一般公众推荐的400 mT静磁暴露限值,且满足标准EN 45502-2-1—2003和GB 16174.2—2015中小于1 mT的静磁场暴露控制限值。

HIGHER-ORDER NODE-BASED TDFEM FOR TRANSIENT ELECTROMAGNETIC ANALYSIS IN RECTANGULAR WAVEGUIDE

Higher-order Time Domain Finite Element Method (TDFEM) based on the nodal inter- polation is proposed for two-dimensional electromagnetic analysis. The detailed algorithms of the method are presented firstly, and then the accuracy, CPU time and memory consumption of the higher-order node-based TDFEM are investigated. The high performance of the presented approach is validated by numerical results of the transient responses of Transverse Electric (TE) field and Transverse Magnetic (TM) field in a rectangular waveguide.

Electromagnetic Response Studies of the Antenna for Deep Water Deep Target CSEM Environments

The Controlled Source Electromagnetic Method (CSEM) is used for offshore hydrocarbon exploration. Hydrocarbon detection in seabed logging (SBL) is a very challenging task for deep hydrocarbon reservoirs. The electromagnetic field response of an antenna is unable to detect deep hydrocarbon reservoirs due to a weak electromagnetic signal response in the seabed logging environment. This work premise deals with the comparison of the electromagnetic signal strength of a new antenna with a straight antenna and the orientation of an antenna for deep target hydrocarbon exploration. Antenna position and orientation (Tx and Ty) was studied using Computer Simulation Technology software (CST) for deep targets in marine CSEM environments. The model area was assigned as (40 ′ 40 km) to replicate the real seabed environment. From the results, the new dipole antenna shows an 804% and 278% increase in electric and magnetic field strength than the straight antenna. An electric (E) and magnetic (H) field component study was done with and without the presence of a hydrocarbon reservoir. Ex and Hz field component responses with the new antenna at the1 kmtarget were measured in a deep water environment. It was analyzed that the antenna shows 53.10% (Ex) and 83.13% (Hz) field difference in deep water with and without a hydrocarbon reservoir at the30 mantenna position from the sea floor. From the antenna orientation results, it was observed that, the electric field Ex and magnetic field Hz responses decreased from 18% to 12% and 21% to 16%, respectively but was still able to detect the deep target hydrocarbon reservoir at the4 kmtarget depth. This EM antenna may open new frontiers for the oil and gas industry for deep target hydrocarbon detection (HC).

Deep learning-based method for detecting anomalies in electromagnetic environment situation

The anomaly detection of electromagnetic environment situation(EMES) has essential reference value for electromagnetic equipment behavior cognition and battlefield threat assessment.In this paper,we proposed a deep learning-based method for detecting anomalies in EMES to address the problem of relatively low efficiency of electromagnetic environment situation anomaly detection(EMES-AD).Firstly,the convolutional kernel extracts the static features of different regions of the EMES.Secondly,the dynamic features of the region are obtained by using a recurrent neural network(LSTM).Thirdly,the Spatio-temporal features of the region are recovered by using a de-convolutional network and then fused to predict the EMES.The structural similarity algorithm(SSIM) is used to determine whether it is anomalous.We developed the detection framework,de-signed the network parameters,simulated the data sets containing different anomalous types of EMES,and carried out the detection experiments.The experimental results show that the proposed method is effective.