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Electromagnetic Compatibility, IEEE Transactions on

Issue 2 • Date May 2001

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Displaying Results 1 - 19 of 19
  • Comments on "Transient radiation of traveling-wave wire antennas

    Page(s): 246 - 248
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (82 KB)  

    Wu and Ruan (see ibid., vol.41, p.120-23, 1999), based on the formalism of Podosenov, Svckis and Sokolov (1995), tried to calculate the electromagnetic radiation field from the current of a traveling wave propagating along a thin curvilinear wire with free ends. In this article the author tries to prove that in the paper of Wu et al. one problem was substituted by another. In fact, another problem, but not that which was formulated by the authors, was solved. It is not the problem of radiation from a curvilinear antenna of finite length, but the problem of radiation from part of an infinite antenna and two external sources emerging under a forcible requirement of satisfying the Lorentz condition for a subsystem, where this condition does not operate a fortiri. The proof is based on the following easily verifiable facts: (1) a coincidence of the expressions for the magnetic field; and (2) a dissimilarity of the expression for the electric field from the formula to a forcible imposing of the Lorentz condition being invalid for subsystems. The author comments on the second point in more detail. View full abstract»

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  • A direction-finding technique for wide-band impulsive noise source

    Page(s): 149 - 154
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    A direction-finding technique for wide-band impulsive electromagnetic interference is presented. An experimental investigation was performed using a spark generator as the impulsive noise source. The signals were captured using a two-antenna array directly sampled at 1 Gs/s. A digital signal processing based correlation technique allowed assessment of the time delay between the antennas. The results in a nonideal radio propagation environment show the bearing can be estimated to an accuracy of 20 View full abstract»

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  • Model of the electromagnetic fields inside a cuboidal enclosure populated with conducting planes or printed circuit boards

    Page(s): 161 - 169
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    We examine the extension of a simple and versatile model of the electromagnetic fields in an equipment enclosure with an aperture to include the effects of loading the enclosure with conducting planes or printed circuit board structures (PCB). Modeling results are compared with experimental measurements of the shielding effectiveness in a cuboidal enclosure loaded with both grounded and ungrounded conducting planes and/or PCBs with a range of grounded and ungrounded tracks. Measurement results are compared with full electromagnetic simulations and the simple model to demonstrate the accuracy and range of validity of the simple model View full abstract»

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  • Some remarks on antenna response in a reverberation chamber

    Page(s): 239 - 240
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    The simple formula, ⟨Pr⟩=(E02 /η)(λ2/8π), for the received power of an antenna with a matched load in an over-moded cavity actually holds for an antenna of any shape and size. This can be seen from the close connection between the correlation tensor of the cavity field at two different points and the imaginary part of the free-space dyadic Green's function View full abstract»

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  • A time-domain physical optics heuristic approach to passive intermodulation scattering

    Page(s): 203 - 209
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB) |  | HTML iconHTML  

    Passive intermodulation (PIM) is a phenomenon which often arises at junctions between different materials. This may be a major issue in tightly packed antenna farms as those typically present on communication satellites. Here, an heuristic nonlinear extension to the time-domain physical optics (TD-PO) is proposed, to take into account electromagnetic scattering at intermodulated frequencies when such a junction is illuminated by two impinging electromagnetic fields at different frequencies. Simulation results are compared with measures to validate the model View full abstract»

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  • An inverse procedure for the return stroke current identification

    Page(s): 155 - 160
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB) |  | HTML iconHTML  

    We propose a procedure to identify the lightning return stroke current characteristics, in the context of return stroke engineering models. The main effort of the up-to-date literature is to find approximate current shapes, which best fit the experimental data. The method hereafter proposed does not follow these approaches, but proposes an inverse algorithm, which allows us to accurately identify the return stroke current for simulated data View full abstract»

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  • Electromagnetic shielding characteristics of optical-fiber feedthroughs

    Page(s): 177 - 186
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB) |  | HTML iconHTML  

    A number of commercially available optical-fiber connector styles ST, SC, and FC were tested to determine the extent to which their use in bulkhead adapter feedthroughs would compromise the shielding of electromagnetic interference for electronic enclosures. Connectors and adapter barrels made from metal, ceramic, and polymer materials were included in the tests. The tests were carried out using a nested reverberation cell and covered a frequency range from 1 to 16 GHz. Although we rely on data acquired by making shielding effectiveness (SE) measurements, we report the results in terms of a transmission cross-section which is the ratio of the power coupled into an enclosure through an aperture to the power per unit area incident on the aperture. The amount of coupling through the feedthroughs we tested varied over 70 dB. The shielding of an all-metal FC connector system was nearly equal to that of a blank reference plate. In some cases, a feedthrough coupled more energy into the enclosure than was coupled through the empty hole required to mount the adapter barrel. Unlike SE, the transmission cross sections do not depend on the volume, shape, or construction materials of the enclosure and can be used to estimate the degradation in the SE for enclosures other than our reference cell. The uncertainties in the reported transmission cross sections are calculated to be ±3 dB and are small compared to the differences between the measured cross sections View full abstract»

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  • A probabilistic model for the response of an electrically short two-conductor transmission line driven by a random plane wave field

    Page(s): 130 - 139
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB) |  | HTML iconHTML  

    A probabilistic approach for the characterization of wiring-harness susceptibility to external interference is presented. The problem of field-coupling onto a uniform, lossless, electrically-short two-conductor transmission line loaded by terminal resistances is considered. The external field is modeled as a plane wave with random parameters. By virtue of the low-frequency assumption, the statistical properties of the induced current magnitude in one of the line loads are derived, for different characterizations of the external wave. Investigated configurations include: waves with random amplitude, waves with random amplitude and polarization, waves with random amplitude and direction of incidence, and waves with random amplitude, polarization and direction of incidence. Analytical expressions for the probability density function of the current (voltage) induced in one of the line loads are derived. The proposed model allows the computation of statistical parameters of interest, such as expected values, variances, and confidence intervals of the currents (voltages) in the line loads View full abstract»

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  • Propagation of double-exponential pulse through Debye medium

    Page(s): 223 - 229
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    The saddle point method is applied to the problem of signal propagation through Debye medium. The steepest descent method is used to calculate the propagation of a double-exponential pulse through Debye medium, and the results are compared with those obtained through Hosono's (1980) method and finite-difference time-domain (FDTD) method. It is found that a Gaussian function can be used to approximate the propagated signal for sufficiently long propagation distance and the analytical representations for the amplitude, center, and width of the propagated pulse are obtained based on the first-order asymptotic representation. An analytical approximation of the saddle points valid for late time is also obtained View full abstract»

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  • Design of multilayered cylindrical shields using a genetic algorithm

    Page(s): 170 - 176
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB) |  | HTML iconHTML  

    The design of infinitely long multilayered cylindrical shields with circular cross-section are considered and a method based on the genetic approach is proposed. An analytical method for the calculation of the shielding effectiveness of a cylindrical shield, consisting of homogeneous layers is presented for the case of an obliquely incident plane wave. By making use of this method, a genetic algorithm is implemented for the design of multilayered cylindrical shields in order to achieve a prespecified shielding effectiveness for a given band of frequencies or a range of angles of incidence View full abstract»

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  • Frequency assignment with complex co-site constraints

    Page(s): 210 - 218
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (132 KB)  

    The adaption of meta-heuristic algorithms such as tabu search and simulated annealing to large frequency assignment problems with complex co-site constraints is described. The constraints considered include frequency separation constraints, intermodulation product constraints and spurious emission and response constraints. Requests for frequencies can also be prioritised. The importance of fast evaluation of the quality of the current assignment by updating techniques is stressed. Additionally, a useful lower bound for assessing the quality of assignments is described View full abstract»

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  • Wavelet packet-based EMI signal processing and source identification

    Page(s): 140 - 148
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    Existing techniques for recognizing and identifying disturbed signals waveforms are primarily based on visual inspection. This paper proposes a wavelet packet based technique to perform a feature extraction from the disturbance signal and a classification of the extracted features in order to identify the possible causes of the disturbance. The same wavelet based procedure is applied to signal compression and denoising in order to make the EMC analysis of the data easier View full abstract»

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  • The transient response of a dipole antenna using a summation approach in technique (SAT)

    Page(s): 197 - 202
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB) |  | HTML iconHTML  

    A novel summation approach in technique (SAT) improving on the usual computation by multiple reflections to find the transient response was presented in a previous paper. This technique leads to accurate answers consisting of relatively few terms. The transient response at large values of time can be found without need to know explicitly and laboriously add all multiple reflections for the whole preceding range of time involved in producing the response. In this paper, the transient response for a realistically modeled pulse generator exciting a dipole antenna modeled as a distributed parameter load is investigated using a generalization of the SAT. A detailed comparison between this technique and the standard superposition of multiple reflections is presented View full abstract»

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  • Measurement of magnetic fields radiated from ESD using field sensors

    Page(s): 187 - 196
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB) |  | HTML iconHTML  

    The goal of this paper is to show that commercial sensors, whose frequency response is not specifically designed, can be effectively used to measure very fast transient fields applying a proper reconstructing procedure based on the knowledge of the sensor transfer function. To do this, it is necessary to characterize a structure supporting a transverse electromagnetic (TEM) field, that will be used to set up a calibration procedure for elementary magnetic field sensors. The approach is completely analytical and allows us to know rigorously the field inside the structure. From the knowledge of this field, the transfer function of the sensor, in amplitude and phase, is evaluated up to 2 GHz. The complete characterization of the sensor allows us to reconstruct the sensed field from its output voltage waveform. The calibration procedure is carried out in time domain and therefore the fast Fourier transform (FFT) algorithm is used to achieve the sensor transfer function, as well as an inverse FFT (IFFT) is necessary to retrieve the transient impinging field. An experimental validation of the procedure shows the consistency of the approach View full abstract»

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  • Power electronic converter EMC analysis through state variable approach techniques

    Page(s): 229 - 238
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    A technique based on the state vector approach and a simple switch device model is proposed for electromagnetic compatibility (EMC) analysis in converter design. The conducted noise spectrum is straightforward computed in the frequency domain for hard switching converters with alternating or direct current input sources. The results are compared with PSpice time-domain simulations mixed with the fast Fourier transform, considering a buck converter. The technique proposed in this paper is appropriate for applications where calculation speed is preferred rather than high precision View full abstract»

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  • Simple estimation of equivalent magnetic dipole moment to characterize ELF magnetic fields generated by electric appliances incorporating harmonics

    Page(s): 240 - 245
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    A simple method of quantifying the ELF (extremely low frequency) magnetic field distribution around electric appliances, which takes the harmonics into account, is newly proposed. The proposed method involves: (1) a simple estimation of the position of an equivalent magnetic dipole moment inside an appliance, using two magnetic field meters; (2) identification of the amplitude of the dipole moment magnetic-field measurements at certain points; and (3) calculation of the magnetic field distribution around the appliance using the estimated dipole moment. In this method, the dipole moment vector is assumed to be a similar value by allowing an uncertainty of 6 dB in the estimated magnetic field, which enables easy estimation of the dipole moment. In addition, the frequency characteristics of the magnetic field are taken into account by considering the harmonic components in the magnetic field waveform. The proposed method was applied to 13 types of appliances, and their equivalent magnetic dipole moments and harmonic components were determined. The results revealed that the proposed method is applicable to many electric appliances. The conditions required for the adoption of the method were also clarified View full abstract»

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  • Compensation of superstrate effects on the resonant behavior of the microstrip ring structure by using an air-gap control

    Page(s): 219 - 223
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (140 KB)  

    In this paper, spectral-domain analysis is utilized to investigate the possibility of compensation of superstrate shielding effects on the resonant behavior of the microstrip ring structure by means of an adjustable air-gap inserted between the substrate and the ground plane. In order to provide the desired amount of tuning, the adjustment of the proper gap thickness is discussed for various structural parameter cases. It is shown that the resonant frequency shift due to superstrate shielding can be compensated, the resonant bandwidth and, hence, the electromagnetic interference can be directly controlled resulting of the proposed tuning scheme View full abstract»

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  • High-frequency electromagnetic field coupling to long terminated lines

    Page(s): 117 - 129
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (340 KB)  

    We present a theory for the EMC problem of electromagnetic field coupling to a long line with arbitrary terminations. The theory is applicable for the high-frequency plane wave electromagnetic field excitations, when the transmission line approximation is no longer valid. Analytical expressions are derived for the induced current along the line, and at the two-line terminals. The coefficients of these expressions are determined using a procedure based on the exact solutions of the integral equation for two similar line configurations, but having a significantly shorter length. The method is, therefore, particularly efficient when considering the electromagnetic field coupling to very long lines. The advantage of the proposed approach is that, in contrast with transmission line approximation, it takes into account high-frequency radiation effects. Furthermore, it allows a considerable reduction in computation time and storage requirements with respect to conventional numerical solutions based on the thin-wire approximation View full abstract»

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  • Transmission link radiation and localized defect contribution

    Page(s): 109 - 116
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    A complete electrical wire link between equipment boxes is analyzed using a theoretical method based on the finite-difference time-domain (FDTD) algorithm. This paper describes how the asymmetry of the transmission line created by different terminations has a direct impact on the radiation level. Thereafter, a transient experimental method is proposed to evaluate the behavior of localized defects on transmission links. The transient results lead to (S) parameters and radiation power. Simulations using the FDTD method validate the experimentation View full abstract»

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Aims & Scope

IEEE Transactions on Electromagnetic Capability publishes original and significant contributions related to all disciplines of electromagnetic compatibility (EMC) and relevant methods to predict, assess and prevent electromagnetic interference (EMI) and increase device/product immunity.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Professor Farhad Rachidi
Swiss Federal Institute of Technology (EPFL)
EMC Laboratory
CH-1015 Lausanne
Switzerland
Phone: +41 (0) 21 693 26 20 (direct)
+41 (0) 21 693 26 61 (secretariat)
Fax: +41 (0) 21 693 46 62
Email: Farhad.Rachidi@epfl.ch
url: http://emc.epfl.ch