Kyohei Fujimoto, Hisashi Morishita · Cambridge University Press eBooks · 2014
Generally, there are some analytical methods to obtain antenna characteristics. However, it can be difficult to obtain the characteristics of small antennas, because they are very limited in dimension and influenced quite sensitively by environmental conditions around them. In many cases, it is hard to verify the performance of small antennas by experiments. For example, when the size of the antenna is extremely small, the radiation resistance becomes too small to be determined accurately. Another case is where the antenna structure is so complicated that precise measurement becomes very difficult to perform.
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Michel Ney · Cairn.info · 2026
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Jean Mahseredjian · Cairn.info · 2026
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Peter Stoltz · The Open Plasma Physics Journal · 2010
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Chen‐To Tai · Deep Blue (University of Michigan) · 1972
http://deepblue.lib.umich.edu/bitstream/2027.42/21324/2/rl2199.0001.001.pdf
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Yun Fan, Yonglin Li, Er‐Ping Li et al. · 2002
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Levent Sevgi · 2015
Modeling and simulation in electromagnetics is reviewed. Fundamental terms and concepts are revisited. Examples are presented.
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P. L. Pritchett · Space Science Reviews · 1985
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J. Brown, Edward Victor George, J. Lippert et al. · IEEE Transactions on Magnetics · 1986
The objectives of this simulation are to support the varlous ElectroMagnetic Gun (EMG)operability requirements, to be maintainable, to duplicate test results or simulate a theoretical system, and to be able to rapidly assess performance and conduct trade studies. This versatile simulation is capable of both performance analysis and some limited component sizing studies. The simulation will permit mixing and matching of various potential EMG components to simulate conceptual or real rapid-fire and single-shot EMG configurations. A generic preprocessor was developed to permit the handling of the large amounts of input data required to operate this simulation. The concept of input data templates is used to minimize the difficulty of specifying runs and generating input data. A simulation executive operates the simulation itself, and a postprocessor catalogs and prepares the output data for both tabular and graphic display.
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2008
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Eric Jones Balaji, Eric Jones, Balaji Krishnapuram et al. · 2007
We present a general purpose simulator that includes electromagnetic scattering tools for buried targets and standard signal processing functionality. Additional modules for genetic or gradient optimization, parallel processing, and multi-aspect target detection via Hidden Markov Models are also available. The entire library is completely scriptable for customization and web enabled for publishing results on the internet. It is also extensible so that users can add modules that address their specific need. The tool runs on both Unix and Windows platforms and includes graphic modules for plotting results and images as well as three-dimensional visualization capabilities for displaying target meshes, currents, and scattered fields. Electromagnetic scattering is calculated via either the Method of Moments (MoM) for arbitrarily shaped three-dimensional perfectly electric conducting (PECs) or dielectric targets above or embedded within a lossy half space. The code uses the combined-field integral equations with the rigorous half-space dyadic Green's function computed via the method of complex images. The simulator offers coarsely parallel capabilities for distributing individual frequencies across a cluster of workstations with near linear speedup.
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Ionuț Tudorancea (4452121), Vlad Porumb (4452139), Alexandru Trandabăţ (4452124) et al. · Figshare · 2017
<p>Electromagnetic/Thermal co-simulation using CST Studio Suit; vertical plane—upper panel; horizontal plane -lower panel.</p>
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FAN YUN · National University of Singapore · 2004
Master's
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Ceylan, Doğa · OpenMETU (Middle East Technical University) · 2019
Electromagnetic launcher (EML) is an electromagnetic accelerator which uses electrical pulse power instead of conventional gunpowder. A large amount of electric current in the pulse waveform flows in the rails and armature. This current creates large magnetic field between rails. As a result of Lorentz force, armature and projectile accelerate. In this study, finite element (FE) model of an EML which includes both pulsed power supply (PPS) circuits with 2~MJ total electrical energy and barrel with 3~m length is developed. In the barrel side of the model, armature movement is simulated with stationary mesh elements using external variable resistances and inductances depending on the armature velocity, position, frequency of the excitation current and inductance gradient. In addition to the current density and magnetic field distribution in the barrel, alternating current (AC), contact, velocity skin effect and back electromotive force (EMF) resistances are investigated for the described switching scenario of the PPS creating pulsed shaped excitation current with 1~MA peak. Muzzle velocity of projectile and armature with 0.125~kg total mass is found to be 2040~m/s. Total muzzle kinetic energy and system efficiency are calculated as 260~kJ and 13%, respectively. Outputs of the electromagnetic simulations of the designed EML are verified with experimental results. Moreover, the effect of lamination thickness of the containment which supports the rails mechanically is observed. Although using containment in the barrel side is a requirement in order not to lose the contact between the rails and armature, it decreases the efficiency of the launcher because of the eddy currents in the conducting containment. It is concluded that using laminations thicker than 10~mm in the containment is not reliable from the electromagnetic point of view. Finally, armature shape optimization study is presented in the last chapter. The objective function of the optimization study is the muzzle kinetic energy of the projectile. Genetic algorithm (GA) is used as the optimization method. Maximum contact current density and electromagnetic deflection pressure on the armature are chosen as constraints. Since the contact resistance affects the distribution of the contact current density, it is also modeled as thin layers between the rails and armature with variable resistivities depending on the contact pressure values acting on each thin layer.
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Yanjie Cao, Wang Chengxue, Huijun Wang et al. · 2008 14th Symposium on Electromagnetic Launch Technology · 2008
Active electromagnetic (EM) armor comprises detection system, intellectual control system, high pulsed-power supply and EM launcher together. And EM launcher consists of drive coil, insulator, pedestal and interception projectile. In order to analyze influences on Ampere forces acting on the interception projectile which result from variations of the pedestal material properties and the structural parameter of drive coil, a 3D model of EM launcher is set up. Simulation of EM launcher is accomplished with a parameterized finite element analysis (FEA) code.
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R.F. Milsom · Philips Journal of Research · 1998
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Chi-Min Yuan · Optical Society of America Annual Meeting · 1991
Optical methods are predominantly used in the photolithography process for linewidth measurement, mask and wafer alignment, and photoresist image formation. As the feature size required for modern semiconductor devices shrinks, it is becoming more difficult to accurately print and measure these fine features on the wafer surface. Simulation of the image formation can aid us in understanding the usefulness and limitation of these optical methods, so that improvement can be made to achieve better accuracy. Approximate theories such as scalar diffraction theory do not explain many of the phenomena, and sometimes rigorous E&M theories beyond Born and Wolf’s level have to be used. Several rigorous scattering models applied in the photolithography areas are introduced first. Most of these models fall into two categories: time-domain solvers and frequency-domain solvers. Maxwell equations are solved by these models to different degrees of rigor to compromise between accuracy and speed. Hardware constraints may exist because of the different algorithms used for the models. The pros and cons of these models are discussed. Finally, the discrepancies existing in today’s models as well as the future needs for more rigorous electromagnetic simulations are explained. Hopefully the photolithography simulation community can benefit from the people who specialize in the E&M field but do not specifically work in the integrated circuit area.
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C. Plechaty, Ryan Glasby, Stuart Slattery et al. · 2023
The understanding of electromagnetic fields is essential for many core applications at Oak Ridge National Laboratory (ORNL). Electromagnetic fieldsplay an important role in particle accelerators, antennas, electric motors, power grids, and are principal part of nuclear fusion. We develop a numerical solver called able to treat the Maxwell system utilizing ORNL's VERTEX framework.
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A. Gole, Shaahin Filizadeh, R.W. Menzies et al. · IEEE Power Engineering Society General Meeting, 2004. · 2004
Summary form only given. Electromagnetic transient simulation programs (EMTP-type programs) are powerful tools for the study of a wide range of power system transient problems. This paper introduces a novel tool in which an EMTP-type program becomes the objective function evaluator for a non-linear optimization algorithm. In this approach, the non-linear optimization program is given control to perform several consecutive runs with a view to minimizing (or maximizing) the desired objective function, which is computed from the results of each simulation run. Since the optimization algorithm strategically selects the parameters for the EMTP run, the overall design process is orders of magnitude faster than that possible from sequential or random (Monte-Carlo type) multiple-runs of the EMTP-type program. The paper discusses the mechanics of the interface as well as design of objective functions. The power of the proposed method is demonstrated through two examples for the design of power electronic converters.
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S. Meighen-Berger, Anatoli Fedynitch, Matthias Huber · arXiv (Cornell University) · 2019
Electromagnetic-Cascades (EmCa) is a Python package for the simulation of electromagnetic cascades in various materials. The showers are modeled using cascade equations and the relevant interactions, specifically pair production, Bremsstrahlung, Compton scattering and ionization. This methodology has the advantage of being computationally inexpensive and fast, unlike Monte Carlo methods. The code includes low and high energy material effects, allowing for a high range of validity of the simulation results. EmCa is easily extendable and offers a framework for testing different electromagnetic interaction models. In combination with MCEq, a Python package for hadronic particle showers using cascade equations, full simulations of atmospheric fluxes can be done.
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