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Electromagnetic Compatibility, IEEE Transactions on

Issue 3 • Date Aug. 1992

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Displaying Results 1 - 25 of 38
  • Comments on a letter by J.R. Wait on magnetic resistivity

    Publication Year: 1992 , Page(s): 375 - 376
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB)  

    In response to the arguments of J.R. Wait (ibid., vol.34, no.2, p.139, 1992), the commenter gives four different reasons for not neglecting magnetic sources.<> View full abstract»

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  • Bistatic scattering of absorbing materials from 30 to 1000 MHz

    Publication Year: 1992 , Page(s): 304 - 307
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    A wideband time-domain reflectometer has been used to evaluate the bistatic performance of the scattering coefficient of RF/microwave absorbers. The scattering coefficient has been measured inside an anechoic chamber in the 30-1000-MHz frequency range in the case of specular reflection. The scattering coefficient increases with incidence angle, and the measurement accuracy is ±2 dB View full abstract»

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  • The natural background levels of 50/60 Hz radio noise

    Publication Year: 1992 , Page(s): 330 - 337
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (636 KB)  

    Measurements of the natural background levels of 50- and 60-Hz radio noise by ELF/VLF (extremely low frequency/very low frequency) radiometers located at various sites around the world are reported. The measurements are made on the magnetic fields of the noise using loop antennas, and they cover the first three harmonics of the power line frequencies (frequencies in the range 50-180 Hz). Due to the likelihood of contamination from local electrical power systems, or even from nonlocal systems, the measurements at each power line frequency were made at adjacent frequencies and the desired noise amplitudes obtained by interpolation. It is shown that the magnetic spectral densities of the natural noise typically lie in the range 20-600 fT/√Hz or, taking the 50/60-Hz frequencies specifically, in the range 150-600 fT/√ Hz. These ranges should be typical for most locations on the Earth's surface and for most seasons View full abstract»

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  • Derivation of common impedance coupling from the transmission-line equations

    Publication Year: 1992 , Page(s): 315 - 319
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    Impedance of the return path common to two circuits can produce a component of crosstalk that is referred to as common impedance coupling. The current of one circuit flowing in this impedance induces a contribution to the crosstalk voltages in the other circuit. This is usually derived on intuitive grounds. The incorporation of the return conductor impedance into the transmission-line equations provides a solution obtained by the author that does not rely on intuition View full abstract»

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  • Time-domain electromagnetic penetration through arbitrarily shaped narrow slots in conducting screens

    Publication Year: 1992 , Page(s): 161 - 172
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1016 KB)  

    A time-domain integral equation is derived for the unknown electric field, or equivalent magnetic surface current, in a narrow slot in a conducting surface, and an efficient and stable numerical method is developed for solving this equation. The contour of the slot in the vanishingly thin conducting surface may be of any shape. The solutions are compared via Fourier transformation with those of the corresponding time-harmonic integral equation, and they are further validated by demonstrating close correlation between values of the calculated field on the shadow side of the conductor and data from laboratory measurements. For numerous slot lengths and shapes, time- and frequency-domain data illustrating the behavior of the slot field and penetrated field are presented and compared with measured results. The stability of the time-domain solution technique is investigated and found to be very high. The response of a slot to an EMP-type (electromagnetic pulse type) pulse is presented as an example View full abstract»

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  • Rapid calculation of near-field fluence of HPM antennas

    Publication Year: 1992 , Page(s): 206 - 213
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    The calculation of near-field fluences of high-power microwave (HPM) antennas is reviewed. Near-fields close to large square or circular antennas are calculated rapidly using the geometric theory of diffraction; one specular and two edge-diffracted rays are used. In the principal planes, accuracy is roughly 2 dB at the -40-dB level, for both uniform and tapered excitations. A universal power density curve is obtained along a line parallel to the aperture, when the distance to the line is normalized by 2D2/λ, and the transverse distance is normalized by D (where λ is the radiation wavelength and D is the aperture width). Diagonal plane fields are calculated using equivalent edge currents via a single numerical integration. Fluence envelopes are obtained in the sidelobe region simply by summing the magnitudes of the two edge rays View full abstract»

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  • The influence of the test fixture on shielding effectiveness measurements

    Publication Year: 1992 , Page(s): 348 - 351
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    In the past, different test cells were used to measure the shielding effectiveness (SE) of materials against electromagnetic radiation, for far-field (or plane wave) conditions. Recently, a new standard was approved. However, some errors may occur, especially in the case of filled conductive plastics, where the conductive layer is not directly accessible from the surface of the material. As well as reporting on some of the difficulties and problems encountered when measuring the SE of this family of materials, the authors propose a different technique for measuring far-field conditions View full abstract»

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  • Frequency analysis of the induced effects due to the lightning stroke radiated electromagnetic field

    Publication Year: 1992 , Page(s): 338 - 344
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    The effects of a lightning stroke to the protection system of the control building of an industrial plant are investigated. The results of a frequency-analysis study of effects connected with point values of the electromagnetic field generated within the building or due to the presence of radiation fields, namely, fields whose harmonic components, characterized by small wavelengths compared to the dimensions of the `victim' circuit, assume nonnegligible values, are reported. These effects are calculated using a procedure based on a field approach. Characterization of the electromagnetic field is ensured by a numerical procedure that permits simultaneous simulation of the protection system and analysis of the electromagnetic field by means of the method of moments used by various authors for the study of direct lightning strokes to thin-wire structures. Two distinct points of impact of the lightning stroke to the protection system are considered, and the results are compared View full abstract»

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  • Phase-locking of strongly coupled relativistic magnetrons

    Publication Year: 1992 , Page(s): 235 - 241
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB)  

    Phase-locking of two strongly coupled S-band relativistic magnetrons in the gigawatt regime was achieved. A single high-voltage pulser drives the two relativistic magnetrons connected by a short waveguide of length ≃nλ/2. Equal power flows in both directions between the magnetrons. The time required to lock is ≃7 ns. Phase-locking lasts for ≃15-20 ns. Phase-locking in the π and 2π modes is demonstrated by direct phase measurement. The RMS peak power is ≃1.6 GW in the π-mode and 400 MW in the 2π-mode. Power density enhancement due to source coherence is directly measured in the radiation field. Locked phase measurements agree with phenomenological modeling of the experiment using a simple van Der Pol model View full abstract»

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  • Skin-effect considerations on transient response of a transmission line excited by an electromagnetic pulse

    Publication Year: 1992 , Page(s): 320 - 329
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (724 KB)  

    The electromagnetic pulse can cause degradation of modern digital and analog devices. Many analytical models have been used extensively to study the susceptibility of equipment related to EMI/EMC (electromagnetic interference/electromagnetic compatibility) engineering, but the emphasis has been mainly on lossless transmission lines. This work takes into account the transient skin-effect of a transmission line exposed to a time-varying electromagnetic field. Beginning with the classical transmission line theory, the transient skin-effect of a transmission line and the equivalent sources due to the external fields are incorporated. As a result, an integral-differential equation is derived. By using the finite-difference-time-domain (FD-TD) approach, the induced voltages onto the line are predicted. There is also a discussion of the numerical approach and the propagation of the predicted induced voltage View full abstract»

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  • Radiated emission from shielded cables by pigtail effect

    Publication Year: 1992 , Page(s): 345 - 348
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    Theoretical analyses and experimental results are carried out on the common mode radiated emission from a shielded cable caused by pigtails. Calculations of the radiation are introduced on the basis of transmission line theory and antenna theory, and are in excellent agreement with the experiment. Certain protective methods and techniques are presented, which exhibit at least 30-dB suppressions against the pigtail effect View full abstract»

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  • Simulation studies of a klystronlike amplifier operating in the 10-100 GW regime

    Publication Year: 1992 , Page(s): 222 - 228
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (588 KB)  

    A coaxial drift tube allows propagation of an ultra high-power relativistic electron beam (500 keV, ⩾100 kA, 100 ns). The modulation of a large-diameter (12.6 cm) intense, relativistic electronic beam (500 keV, 16 kA) by an external microwave source via particle simulation is studied. The annular beam, enclosed within a coaxial drift tube, is found to be fully modulated by a low-power external RF source at a frequency of 1.3 GHz. It is shown that for such an intense beam, a highly nonlinear interaction takes place at the modulating gap, producing highly coherent bunches of electrons. This finding is similar to earlier research in which such modulations were studied for an intense beam propagating in a hollow drift tube. It is further shown that, unlike the hollow drift tube case, the coaxial configuration is easily scaled to high power. Here, a very large diameter (26 cm) intense beam (460 keV, 100 kA) is fully modulated at 1.3 GHz to obtain 31 GW of RF beam power View full abstract»

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  • Finite difference time domain calculations of antenna mutual coupling

    Publication Year: 1992 , Page(s): 357 - 359
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    The finite-difference-time-domain (FD-TD) technique is applied to calculations of self and mutual admittances between wire antennas. The results are compared with results obtained using the method of moments. The agreement is quite good, indicating the possibilities for FDTD application to antenna impedance and coupling View full abstract»

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  • Potential for a unified topological approach to electromagnetic effects protection

    Publication Year: 1992 , Page(s): 267 - 274
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (824 KB)  

    An approach to the potential unification technology for a wide spectrum of electromagnetic environments (EMEs) is presented. Of particular interest is the protection of complex electronic systems. An electromagnetic topological approach is utilized to develop a consistent shielding protection method. Applicable electromagnetic topological techniques are presented. The varying characteristics of the various EMEs, for electromagnetic sources both internal and external to the system, are described. The EMEs considered include: electromagnetic interference/compatibility (EMI/EMC), lightning electromagnetic pulse (LEMP), nuclear EMP (NEMP), and high-power microwaves (HPMs). Existing protection practices, incompatibilities, and suggested remedies are discussed. A quantitative and generalized topological protection approach and the basic technological means for applying it are presented View full abstract»

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  • Low frequency shielding effects of a conducting shell with an aperture: response of an internal wire

    Publication Year: 1992 , Page(s): 370 - 373
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    Finite-difference-time-domain (FD-TD) predictions have been used, with up to a million time steps, to accurately characterize wire resonances below aperture cutoff for a wire shorted at its base and located within a conducting shell pierced by an aperture. Only a modest shielding effect was observed below cutoff for perfectly conducting shells with varying size apertures. The amplitudes of the wire resonances rose as 1/ω2 as frequency decreased. The Q of the wire resonances also increased rapidly with decreasing frequency. These effects were nearly offsetting, leaving the energy in each wire resonance only slightly reduced from the unshielded wire responses as the aperture size varied. This reduction only increased modestly with smaller aperture size View full abstract»

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  • Maximization of electromagnetic response at a distance

    Publication Year: 1992 , Page(s): 148 - 153
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    In designing an electromagnetic illuminator which is to excite a system at some distance away from the source (compared to wavelength and illuminator antenna dimensions), there are various factors to be considered. Resonant waveforms (approximate damp sinusoids) are used for maximum coupling. The various factors are then the source amplitude and pulse width, and the transfer functions for the antenna, propagation, response of the system exterior, and response of the system interior. These are combined to estimate and optimize the overall system response View full abstract»

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  • Response to `The magnetic conductivity and wave propagation'

    Publication Year: 1992 , Page(s): 376 - 377
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    The commenter, in response to the correspondence of J.R. Wait (ibid., vol.34, no.2, p.139, Apr. 1992), presents three objections to the systematic use of the Helmholtz equation in place of the wave equation for time-harmonic problems View full abstract»

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  • The concept of dominant effect in EMC

    Publication Year: 1992 , Page(s): 363 - 367
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (428 KB)  

    The net effect one is trying to reduce (crosstalk, conducted emissions, radiated emissions, etc.) generally is the sum of two or more components, one of which is dominant. The circuit elements in the device under test often affect only one component. Changing the circuit element that effects the component which is not dominant will not significantly reduce the overall effect. This simple concept is examined in the context of three common EMC problems: crosstalk, conducted emissions, and radiated emissions. The intent in doing so is to increase the awareness of this concept so that frustrations and delays in reducing the total effect will be avoided View full abstract»

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  • Comparison measurements of currents induced by radiation and injection

    Publication Year: 1992 , Page(s): 360 - 362
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    Measurements that show significant differences between currents measured in individual wires of a bundle due to equal current excitations by external radiated fields or by bulk injection are reported. This raises concern whether bulk current injection is a reliable technique for EMC work View full abstract»

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  • Advances in virtual cathode microwave sources

    Publication Year: 1992 , Page(s): 252 - 258
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB)  

    The evolution of the virtual cathode microwave source and its current performance are described. Explosive generator driven virtual cathode oscillators, resonant cavity sources, and phase-locking and amplifier sources are covered. Areas for future development are discussed View full abstract»

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  • High-power microwave test facility based on double-anode relativistic tetrode (DART) oscillators

    Publication Year: 1992 , Page(s): 229 - 234
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB)  

    High-power microwave (HPM) sources for testing systems and components at high peak powers and high energy fluences are described. Peak powers of up to 400 MW are radiated using a 150 ns, 650 kV pulse-power device to drive a class of microwave tubes termed double-anode relativistic tetrode oscillators. The DART class of devices is particularly useful for facility testing because the devices (1) provide pencil beam output at high exposure levels, (2) are fully tunable over ~25% bandwidth, and (3) are compatible with a wide variety of low-cost horns which provide various antenna gains. A 1 MW L-band magnetron provides power densities and energy fluences exceeding 500 W/cm2 and 2 mJ/cm2 for μs pulse lengths at repetition rates to 120 Hz. The RF test environment is characterized using redundant in-situ and free-field RF diagnostics and a VAX-based data acquisition and archival system. The capability for both single-shot and repetitive testing is discussed View full abstract»

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  • On the coupling of microwave radiation to wire structures

    Publication Year: 1992 , Page(s): 183 - 188
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB)  

    The general aspects of the excitation of wire structures under microwave illumination are presented and discussed. Numerical, analytical and experimental results are provided. A simple procedure is presented for bounding the response of certain canonical configurations. Results are obtained for a terminated single wire over a ground plane and for a two-wire transmission line under plane wave illumination. The variation of the induced current with the dimensions and frequency is considered. It is shown that the TEM (transverse electromagnetic) mode current is a suitable approximation for the wire current with line separations up to and exceeding a wavelength View full abstract»

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  • An expanding-grid algorithm for the finite-difference time-domain method [EM deposition in human body]

    Publication Year: 1992 , Page(s): 277 - 283
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    Recognizing that EM deposition in the human body at higher frequencies is primarily superficial (in the eyes, the frontal lobe of the brain, gonadal area, etc.), the authors have modified the finite-difference-time-domain (FD-TD) algorithm to use a logarithmically expanding grid rather than a uniform grid. The expanding-grid algorithm allows cell-to-cell expansion factors that can differ along the three axes. Expansion factors α of the order of 1.03 to 10.8 have been found to give internal fields that are in excellent agreement with those obtained analytically for 2-D homogeneous and layered lossy cylinders and for 3-D homogeneous spheres. In air outside the body, the increasing cell sizes are obviously acceptable and are still a small fraction of the free-space wavelength (<λ0/10). In the interior of the body, the increasing cell sizes are also acceptable because there is little or no energy deposition in these regions, particularly at high frequencies View full abstract»

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  • Accuracy in outdoor isotropic measurements of multiple-source, multiple-frequency EM fields

    Publication Year: 1992 , Page(s): 299 - 303
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    Narrow- and broadband measurement systems have been calibrated and used to characterize the electric field strength in regions close to 69 telecommunication antennas emitting a total power of nearly 190 kW. The differences in decibels between narrow and broadband outdoor measurement results are always within 0.71 dB, giving a mean value of 0.08 dB. An error analysis referring to the use of both measurement systems has been done. From a statistical analysis of the obtained results, the assigned total systematic error of the isotropic electric field measurements in the frequency domain is 1.82 dB for both systems. The inherent systematic error in the measurement procedure is about 1.57 dB View full abstract»

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  • A simple transmission line model for narrow slot apertures having depth and losses

    Publication Year: 1992 , Page(s): 173 - 182
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    A simple transmission line model is given to approximately represent a narrow slot aperture having depth when the conductivity of the conducting plane (and slot walls) is large but not necessarily infinite and when somewhat lossy gaskets are placed in the slot. Slot and gasket dimensions, in addition to the electrical parameters of the conducting plane and gasket, are restricted so that gasket- and wall-loss-effects only need to be included locally (near the slot cross section) and additionally so that the slot voltage is nearly constant locally (however diffusion into the depth of the slot is considered when very lossy gaskets are introduced). Normal incidence is emphasized since this is typically the most important case for slots that are not too long compared to the wavelength. The transmission line model is used to obtain simple approximate formulas for resonant quality factor, slot voltage, penetrant fields, and transmitted power. Low frequency quantities including magnetic dipole moments are also obtained. Gaskets with air gaps are considered and optimum choices for electrical parameters are discussed 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