Electromagnetic Field In Frequency Domain Research Articles

Analysis of a cusped helicon plasma thruster discharge

Experiments and simulations are used to analyze a compact helicon plasma thruster with a cusp in its internal magnetic field. The former rely on a compensated Langmuir probe and a Faraday cup, while the latter employ a hybrid PIC/fluid transport model combined with a frequency-domain electromagnetic field model. Measurements serve to tune the anomalous transport parameters of the model and overall show the same trends as the numerical results, including a secondary peak of electron temperature downstream in the magnetic nozzle, where electron cyclotron resonance conditions for the 13.56 MHz excitation frequency are met. The cusp plays a central role in determining the plasma losses to the walls and the profile of electron temperature, which in turn defines the excitation and ionization losses. While losses to the rear wall are reduced, losses to the lateral wall are increased, which, together with the low production efficiency, limit the performance of the device.

Multiphysics Computing of Challenging Antenna Arrays Under a Supercomputer Framework

A parallel multiphysics simulation solver is developed to solve electromagnetic-thermal-mechanical coupling for some challenging large-scale antenna arrays. To achieve high scalability of supercomputer architectures, we reconstruct the preconditioned BiCGSTAB method and the non-overlapping domain decomposition method, so that the most resource-intensive matrix factorization steps can be performed in parallel independently within subdomains. The electromagnetic and thermal fields are solved separately, while coupled through the dissipated power and the temperature-dependent material parameters; after thermal steady state is reached, the mechanical simulation is stimulated subject to the temperature rise. The accuracy of electromagnetic-thermal coupling and thermal stress solution are first validated, and then the strong/weak parallel scalability experiments of the developed multiphysics solver are performed on supercomputer. Finally, an extremely challenging antenna array is simulated using the proposed solver, where to our best knowledge we bring the scale of multiphysics simulations excited by frequency-domain electromagnetic fields to the order of billion unknowns for the first time.

Research on Electromagnetic Compatibility of High Frequency Switching Power Supply Based on Harmonic Balance Finite Element Method

With the rapid development of electronic technology, high frequency switching power supply has been widely used in various electrical equipment, and its electromagnetic interference has attracted more and more attention. In this paper, the harmonic balance finite element method is used to solve the electromagnetic compatibility of high frequency switching power supply. In this method, the coefficients of sine wave are applied to represent the waveform, and the solution is generated by linear synthesis. We propose to combine it with the finite element method to solve the steady-state response of electromagnetic field in frequency domain. It is proved the method we proposed is superior to the traditional time domain method.

Analytical, numerical and experimental analysis of induction heating of graphite crucible for melting of non‐magnetic materials

This study presents analytical formulation used for design of helical coil for induction heating of solid and hollow cylindrical non-magnetic workpiece (graphite crucible). This formulation is applied for estimation of the active power in graphite crucibles and reactive power drawn by the induction coil in presence of different wall thickness (30, 20, 10 and 5 mm) of graphite crucibles at different frequency (1-50 kHz). Magnetic field produced by induction coil is estimated by using empirical factors suggested by kNagaoka et al. Induction heating processes, i.e. electromagnetism and heat transfer physics are mathematically modelled by Maxwell and Fourier equations, respectively. Finite-element method is used to solve the electromagnetic field in frequency domain and heat transfer in transient domain. Numerical analysis is carried out by using two-dimensional axisymmetric geometry. Analytical results and numerical results are compared and are found to be in good agreement with each other. Experimentally obtained coil voltage and graphite crucible temperature were compared with numerical results and the authors found that they also match very well confirming the validity of their assumptions in analytical/numerical approach.

Design and analysis of a square spiral nano-rectenna for infrared energy harvest and conversion

We have designed a novel nano-rectenna composed of a square spiral nanoantenna and a rectifier (Au-TiOx-Ti diode) for harvesting infrared energy and its conversion. The three-dimensional frequency-domain electromagnetic field calculation software based on the finite element method is used at infrared frequencies (5~30 μm) to analyze the optoelectronic properties of the proposed nano-rectenna. The simulation results indicate that three types of resonance wavelengths and local field enhancement are significantly influenced by the geometric parameters of the square spiral nanoantenna, as well as the structure and composition of the dielectric layer. An output current of the designed nano-rectenna is approximately at tens of nA with an incident electric field intensity of 1 V/m. Moreover, the photoelectric conversion efficiency is calculated to reach about several percentages. The mechanism on the optoelectronic performance of the nano-rectenna is deeply discussed. As a result, the optimized structure may lead to important applications in infrared detectors, novel cell devices and integrated photonic circuits.

Design of a sector bowtie nano-rectenna for optical power and infrared detection

We designed a sector bowtie nanoantenna integrated with a rectifier (Au–TiO x –Ti diode) for collecting infrared energy. The optical performance of the metallic bowtie nanoantenna was numerically investigated at infrared frequencies (5–30 μm) using three-dimensional frequency-domain electromagnetic field calculation software based on the finite element method. The simulation results indicate that the resonance wavelength and local field enhancement are greatly affected by the shape and size of the bowtie nanoantenna, as well as the relative permittivity and conductivity of the dielectric layer. The output current of the rectified nano-rectenna is substantially at nanoampere magnitude with an electric field intensity of 1 V/m. Moreover, the power conversion efficiency for devices with three different substrates illustrates that a substrate with a larger refractive index yields a higher efficiency and longer infrared response wavelength. Consequently, the optimized structure can provide theoretical support for the design of novel optical rectennas and fabrication of optoelectronic devices.

辺有限要素法による周波数領域電磁界解析から得られる複素対称線形方程式におけるマルチカラーオーダリングを使用した前処理付きCOMRTR法の並列性能

辺有限要素法による周波数領域電磁界解析から得られる複素対称線形方程式におけるマルチカラーオーダリングを使用した前処理付きCOMRTR法の並列性能

ERMES: A nodal-based finite element code for electromagnetic simulations in frequency domain

In this work we present a new finite element code in frequency domain called ERMES. The novelty of this computational tool rests on the formulation behind it. ERMES is the C++ implementation of a simplified version of the weighted regularized Maxwell equation method. This finite element formulation has the advantage of producing well-conditioned matrices and the capacity of solving problems in the low (quasi-static) and high frequency regimens. As a consequence of this versatility, ERMES has been applied successfully to microwave engineering, antenna design, electromagnetic compatibility and eddy currents problems. This paper describes the main features of ERMES and explains how to use this numerical tool for computing electromagnetic fields in frequency domain. Program summaryProgram title: ERMESCatalogue identifier: AEPV_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEPV_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 223528No. of bytes in distributed program, including test data, etc.: 35954099Distribution format: tar.gzProgramming language: C++.Computer: Any computer with Microsoft Windows (32-bits or 64-bits) installed.Operating system: Microsoft Windows 32-bits or 64-bits.RAM: Problem dependent. See [1] for examples of computational performance.Classification: 10.External routines:GiD [5] is used for geometrical modeling, data input, meshing and visualization of results.Nature of problem:Time-harmonic Maxwell equations.Solution method:Finite element formulation based on the weighted regularized Maxwell equation method [2, 1, 3, 4].Additional comments:!!!!! The distribution file for this program is approximately 35 Mbytes and therefore is not delivered directly when the download or Email is requested. Instead a html file giving details of how the program can be obtained is sent. !!!!!Running time:Problem dependent (see [1]).

Effective skin depth of EM fields due to large circular loop and electric dipole sources

Definition and concept of plane wave skin depth is applied to study the effective skin depth due to large circular loop and horizontal electric dipole sources, and attempt is made to illustrate its application to the real field survey design and data interpretation problems. The effective skin depth, the depth at which the amplitude of a frequency-domain electromagnetic field due to a large circular loop source or an electric dipole source falls to 1/e of its value at surface of a homogeneous half space, is compared with the usual plane wave skin depth for variation of different survey and model parameters, viz. source frequency, source moment or loop dimension, source-receiver offset and half space conductivity. The results show their characteristic variations, and depict that the effective skin depth due to large loop source and/or electric dipole source depends on source-frequency, source moment, source-receiver offset and half-space conductivity. The effective skin depth may vary from a fraction of plane wave skin depth in near vicinity of the source to more than twice the plane wave skin depth at points away from the source. However, for large source-receiver offsets and/or high source frequencies and half-space conductivities, it tends to the plane wave skin depth. For receiver positions in near vicinity of the source, the effective skin depth curves exhibit variations specific to the source, and show different characteristic variations for different sources, whereas for receiver positions away and far away from the source, the effective skin depth curves show similar characteristic variations for all sources, irrespective of nature and geometry of the source. The results depict distinctive effect of geometry and nature of the source on effective skin depth. The examples presented for illustrating the application of effective skin depth depict that effective skin depth has direct relation with the EM response of the local source over the layered earth and thus, can be used as an aid for estimating the optimum parameters in EM survey design and data interpretations.

Analysis of electromagnetic field transient on branch feeders by numerical electromagnetic field computation

AbstractThis paper presents the fundamental surge phenomenon when a step voltage is applied to a horizontal line above the ground which has branch feeders. We study line current and voltage at joint with the method of moments that calculates electromagnetic field in frequency domain. It is widely noted that the current reflection factor changes to a third at the junction of the same three lines in conventional transmission line theory based on TEM wave, and the stepwise current reflected appears overlapping to the incident current. On the other hand, the reflected current from the joint shows the inductive characteristic or the capacitive one depending on the angle between lines, which varies gradually and not stepwise in our numerical analysis considering TM wave. The time characteristic of the voltage at joint depends on the angles also, and the peak voltage slightly exceeds the voltage by the transmission line theory. These phenomena are caused by the electromagnetic coupling between the main line and branch lines. In addition to the computer simulations, we measured the currents in the reduced‐scale model lines and the results show the validity of our analysis regarding changes of the reflected current depending on the angles. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(2): 1–8, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10176

Shifted-frequency internal equivalence

The shifted frequency internal equivalence (SFIE) theorem involving inhomogeneous regions is introduced and proven. For a lossless inhomogeneous region using a vector Green's theorem and potential formulation, it is shown that the frequency-domain electromagnetic field at frequency /spl omega/ inside the region can be obtained using a set of equivalent volume and surface currents radiating in free space and at the different frequency /spl omega//sub 0/. The equivalent currents thus obtained are functions of the two frequencies, electric- and magnetic-volume-type sources of the original problem, material parameters, and the original field phasors at /spl omega/, and they only exist inside the region and on its boundary. A direct application of this equivalence is that it can be used to construct an internal equivalence at a shifted frequency for electromagnetic scattering problems if data are needed in a band of frequency. /spl omega//sub 0/ can be kept constant while the incident field frequency changes and, as a result, full computation of fields at each different frequency for volume-type equivalent sources can be avoided.

3D finite element calculation of harmonic electromagnetic fields

A procedure is implemented using edge-type elements for the solution of frequency-domain electromagnetic field problems. It consists of a coupled simple-layer integral equation procedure for an interior-exterior problem where a homogeneous object is under external excitation. In addition, a hybrid finite-element procedure using vectors E or H as the state variable for efficiently handling interior homogeneities is given. Some representative results are presented. >

Moment method with isoparametric elements for three-dimensional anisotropic scatterers

A new method for computing the frequency-domain electromagnetic fields scattered from, and penetrating into, arbitrarily shaped, three-dimensional, lossy, inhomogeneous anisotropic scatterers is presented. The method is based on a general volume integro-differential formulation of the scattering problem, and consists of the numerical solution of the coupled integral equations by the moment method and point matching. A particularly powerful feature of this method is that the numerical model of the scatterer is obtained by parametric volume elements and the basis functions used to represent the field within each element are the same used in the finite-element method. Element integration problems due to the singular kernel of the integral equations are treated in some detail. Numerical results for both the isotropic and the anisotropic spherical scatterer are presented, including comparisons with results obtained by different numerical methods for the isotropic cases considered. The capability of the numerical code presented here to deal with cases where the material parameters of the scatterer are given by singular matrices is discussed for two particular examples.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Extended Least Squares Iterative Techniques in the Solution of Electromagnetic Scattering by Penetrable Objects

The iterative computation of frequency-domain electromagnetic fields scattered by arbitrarily shaped, inhomogeneous, penetrable objects is investigated. A domain-type integral equation is solved by minimizing iteratively a global root-mean-square error. Starting with an arbitrarily chosen initial estimate and employing different variational functions, a general, flexible, iterative procedure is developed in which a monotonic decrease in the error is enforced in each iteration step. Different iterative schemes are obtained by employing different, suitable variational functions. Several typical schemes are compared numerically and numerical results are presented for one- and two-dimensional scattering problems. In the latter both TE- and TM-problems are investigated.