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Numrering	Referens	Omslagsbild	Hitta
1.	Ahmad, Noor Azlinda, 1978-, et al. (författare) Radiation Field Spectra of Long-duration Cloud Flashes Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. Tidskriftsartikel (refereegranskat)abstract The radiation electric fields produced by long-duration cloud flashes have been Fourier analyzed to determined the frequency spectrum in the range of 10 kHz to 10 MHz. The flashes were recorded within a distance of less than 20 km. The spectrum was normalized to 50 km distance and it shows a f-1 dependence within the entire frequency range.
2.	Becerra, Marley, et al. (författare) On the interaction of lightning upward connecting positive leaders with humans 2009 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - USA : IEEE. - 0018-9375 .- 1558-187X. ; 51:4, s. 1001-1008 Tidskriftsartikel (refereegranskat)abstract Upward connecting leaders can be initiated from humans under the influence of lightning downward stepped leaders, thereby causing severe injuries. In order to improve the scarce knowledge about the interaction of upward connecting leaders with humans, a self-consistent model based on the physics of leader discharges is used in this paper. Furthermore, a current-generation-type return-stroke model is applied to calculate the current pulse produced during the neutralization of unsuccessful aborted upward leaders. It is estimated that an upward connecting leader can be initiated even when the victim is located several tens of meters away from the lightning channel. However, the lightning exposure to a direct strike and to an aborted leader is found to be reduced by 50% and 70%, respectively, when an individual standing straight adopts the squat position. In the case of an aborted upward leader, it is estimated that a short-duration pulse of opposite polarity in the kiloampere range would be produced by the neutralization of the leader charge. Rough estimates of the total energy dissipated in the victim's body by the current of an aborted unsuccessful upward leader range between hundred and thousand joules.
3.	Carlberg, Ulf, 1978, et al. (författare) Numerical study of position stirring and frequency stirring in loaded reverberation chamber 2009 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 51:1, s. pp. 12-17 Tidskriftsartikel (refereegranskat)abstract A numerical model of a loaded reverberation chamber is used to study the effectiveness of 3-D position stirring and frequency stirring. The numerical model is based on thin wires, the moment method, and a cavity Green's function. The average power transfer level between two dipole antennas is compared to the average power transfer level between a dipole antenna and a loop antenna. The two transmission levels should ideally be the same, as both the dipole and the loop are treated as being lossless and impedance matched. The standard deviation of the level differences is a measure of the accuracy of the chamber, and this is used to estimate the stirring effectiveness. It is shown that frequency stirring must be done over a larger bandwidth than the average mode bandwidth to be effective. The 3-D position stirring is also shown to be much more efficient than expected.
4.	Carlsson, Jan, et al. (författare) Numerical Study of Position Stirring and Frequency Stirring in a Loaded Reverberation Chamber 2009 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 51:1, s. 12:19- Tidskriftsartikel (refereegranskat)
5.	Carlsson, Jan, 1962, et al. (författare) Transmission through corrugated slots 1995 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9375 .- 1558-187X. ; 37:1, s. 114-121 Tidskriftsartikel (refereegranskat)
6.	Colombi, Davide, et al. (författare) Efficient Whole-Body SAR Assessments by Means of Surface Scan Measurements 2014 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 56:3, s. 539-548 Tidskriftsartikel (refereegranskat)abstract In this study, an experimental method has been investigated for efficient assessments of whole-body specific absorption rates (SAR) from radio base station antennas. Using surface amplitude measurements of the electric field components together with an integral equation technique, a method is obtained which is not biased to specific antenna designs or phantom shapes. For realistic material parameters, it has been found that only the amplitude of the tangential field components over the phantom boundary is needed to accurately assess whole-body SAR, which makes the proposed method well suited for integration with commercially available SAR measurement systems. The method has been validated with simulations and measurements. Compared with a volumetric scan, and for the cases investigated, the measurement time was reduced with a factor larger than 3 while keeping the relative error smaller than 8%.
7.	Cooray, Vernon (författare) A novel procedure to represent lightning return strokes : current dissipation return stroke models 2009 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - USA : IEEE. - 0018-9375 .- 1558-187X. ; 51:3, s. 748-755 Tidskriftsartikel (refereegranskat)abstract Engineering return stroke models available in the literature can be divided into two categories, namely, current propagation models and current generation models. Based on the theory of pulse propagation along transmission lines in the presence of corona, a third procedure to describe return strokes, which, in fact, is the inverse of current generation models, is introduced. Models based on the new concept are called current dissipation models. In the current generation models, the corona currents generated by the neutralization of the corona sheath travel downward and the cumulative effects of these corona currents generate the return stroke current. In current dissipation models, the return stroke is initiated by a current pulse injected into the core of the leader channel at ground level. This injected current pulse travels upward with speed vc . If the return stroke channel is treated as a transmission line, then this speed is equal to the speed of light. The propagation of this pulse along the central core initiates the neutralization of the corona sheath leading to the release of corona currents into the central core. In contrast to current generation models in which corona currents travel downward, these corona currents travel upward along the core. The speed of propagation of the corona pulses upward along the core is also equal to vc. The corona currents, being of opposite polarity, lead to the dissipation of the injected current pulse. As in the case of current generation models, a current dissipation model can be described completely by any three of the following four parameters. They are: 1) channel base current; 2) spatial variation of the return stroke velocity; 3) spatial variation of the corona decay time constant; and 4) the spatial variation of the positive charge deposited by the return stroke on the leader channel. It is also shown that current propagation models available in the literature are special cases of current dissipation models.
8.	Cooray, Vernon, et al. (författare) Engineering Lightning Return Stroke Models Incorporating Current Reflection From Ground and Finitely Conducting Ground Effects 2011 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 53:3, s. 773-781 Tidskriftsartikel (refereegranskat)abstract A return stroke model that incorporates a reflected wave from ground without introducing any current discontinuities at the return stroke front is introduced. The incident current is treated using current generation concepts and the reflected current using current dissipation concepts. It is shown that the effect of the reflected current wave is to cause flattening of close electric field waveforms within about 10 mu s. Additionally, it is shown how a return stroke model could be utilized to study the effect of ground conductivity on the return stroke current. The results show that the peak time derivative of current in lightning strokes terminating on poorly conducting ground is significantly lower than in the case of highly conducting ground. The model is also used to predict the spatial variation of return stroke velocity. The results show that the return stroke velocity increases initially, reaches a peak, and then decays with increasing height.
9.	Cooray, Vernon, 1952-, et al. (författare) Field-to-Transmission Line Coupling Models With Special Attention to the Cooray-Rubinstein Approximation 2021 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9375 .- 1558-187X. ; 63:2, s. 484-493 Tidskriftsartikel (refereegranskat)abstract There are three equivalent procedures to evaluate the voltages induced by lightning on power lines, namely, the Agrawal-Price-Gurbaxani model, the Taylor-Satterwhite-Harrison model, and the Rachidi model. The Cooray-Rubinstein approximation is a procedure used by scientists and engineers to estimate the horizontal electric field from the lightning that is used in the induced voltage calculations for lines located over a finitely conducting ground. The Cooray-Rubinstein approximation is usually incorporated in calculating the induced overvoltages using the Agrawal-Price-Gurbaxani model. In this article, it is shown how this approximation could be incorporated into the other two coupling models. The resulting coupling equations are compared to each other by calculating the voltages induced on two idealized overhead transmission lines.
10.	Cooray, Vernon, 1952-, et al. (författare) Formulation of the Field-to-Transmission Line Coupling Equations in Terms of Scalar and Vector Potentials 2017 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 59:5, s. 1586-1591 Tidskriftsartikel (refereegranskat)abstract More than 60 years ago, Prof. S. Rusck introduced a coupling model to take into account the interaction of lightning-generated electromagnetic fields with overhead power transmission and distribution lines. The model which assumes that the ground is perfectly conducting has served the power system research community for many decades. Recently, it was found that this model is not complete because some of the forcing terms in the relevant transmission line equations, which are based purely on the scalar and vector potentials, were missing. In the present paper, the correct transmission line equations pertinent to the interaction of external electromagnetic fields with overhead lines, described in terms of scalar and vector potentials, are derived by incorporating the effects of a finitely conducting ground. The model presented in this paper can be considered as a correction and an extension of the Rusck model to account for a finitely conducting ground.
11.	Cooray, Vernon (författare) Horizontal Electric Field Above- and Underground Produced by Lightning Flashes 2010 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 52:4, s. 936-943 Tidskriftsartikel (refereegranskat)abstract The horizontal electric field both at points above and below ground in the vicinity of lightning return strokes were evaluated by numerical solution of Sommerfeld's integrals. Results are presented for ground conductivities in the range of 0.01-0.0001 S/m. The results are compared with the following approximate procedures used in the literature to calculate horizontal electric fields: 1) the surface impedance approximation; 2) the quasi-static approximation frequently used in lightning protection standards; and 3) Cooray's simplified formula for the computation of underground electric field. Based on this comparison, the distance range in which these approximations are valid is obtained. The results obtained show that: 1) The surface impedance approximation can generate correct horizontal electric field when the distance to the point of observation is larger than about 50, 200, and 500 m for ground conductivities of 0.01, 0.001, and 0.0001 S/m, respectively. 2) It is necessary to include propagation effects in the magnetic field that is being used as an input in the surface impedance expression when it is being used to calculate the horizontal electric field. 3) Cooray-Rubinstein approximation gives exact results when it is being used to calculate the horizontal electric field aboveground generated by cloud flashes. 4) Cooray's simplified formula connecting the surface horizontal electric field to the underground one gives accurate results, provided that the horizontal electric field at the surface of the ground, which is used as an input, is calculated accurately and the depth of the point of observation is kept much less than the distance to the point of strike.
12.	Cooray, Vernon, et al. (författare) On the Relationship Between the Signature of Close Electric Field and the Equivalent Corona Current in Lightning Return Stroke Models 2008 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 50:4, s. 921-927 Tidskriftsartikel (refereegranskat)abstract Engineering return stroke models can be categorized either as current generation (traveling current source type) models or current propagation (transmission line type) models. The current generation models are described among other parameters by a corona current distributed along the channel. Recent studies show that there is equivalence between the models of current generation and current propagation types. Due to this equivalence, any engineering return stroke model of current propagation type can be described in terms of an equivalent corona current per unit channel length. The measurements conducted within 10-500 m from triggered lightning Hashes show that the electric field of subsequent return strokes at these distances flattens within 15 mu s or so. In this paper, the constraints imposed by this feature on the temporal and spatial variation of the equivalent corona current are investigated. The results show that in order for the close fields to flatten within 15 mu s or so, the equivalent corona current, should be bipolar and the corona current wave shape at late times should be identical to that of the longitudinal current time derivative. This is in contrast to most of the engineering models of current generation type, in which the corona current is assumed to be unipolar.
13.	Cooray, Vernon (författare) Propagation effects due to finitely conducting ground on lightning-generated magnetic fields evaluated using sommerfeld's integrals 2009 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - USA : IEEE. - 0018-9375 .- 1558-187X. ; 51:3, s. 526-531 Tidskriftsartikel (refereegranskat)abstract The effects of finitely conducting ground on the signature of lightning-generated magnetic fields at ground level were evaluated by numerical solution of Sommerfeld's integrals. Results are presented for distances between 10 m to 1 km from the lightning channel and for ground conductivities in the range of 0.01 and 0.0001 S/m. The results obtained from the exact theory are compared with the predictions of two frequently used analytical approximations to Sommerfeld's equations. Based on that comparison, the limits of validity of these approximate theories are obtained.
14.	Cooray, Vernon, et al. (författare) The Electromagnetic Fields of an Accelerating Charge : Applications in Lightning Return-Stroke Models 2010 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 52:4, s. 944-955 Tidskriftsartikel (refereegranskat)abstract In the literature, three procedures have been used to calculate the electromagnetic fields from return strokes. In the first technique, the source is described only in terms of current density and the fields are expressed entirely in terms of the return-stroke current. In the second technique, the source is expressed in terms of the current and the charge densities and the fields are given in terms of both the current and the charge density. In the third technique, the fields are expressed in terms of the apparent charge density. The fields are connected to the source terms through the vector and scalar potentials. In this paper, the standard equations for the electromagnetic fields generated by an accelerating charge are utilized to evaluate the electromagnetic fields from lightning return strokes. It is shown that the total fields evaluated at any distance using these expressions are identical to those obtained using other techniques. However, the composition of the terms that vary as 1/R, 1/R2, and 1/R3 of the total electric field is different from those of other formulations. In the case of the transmission-line model, where the return stroke is described as a current pulse propagating with uniform velocity, radiation emanates only from the bottom of the channel where current is generated. When the speed of propagation is equal to the speed of light, the total field throughout the entire space becomes radiation. The procedure is also applied here to obtain the electric fields of the traveling-current-source model. The electric fields obtained for this case, too, agree with the previous study. It is also shown how the equations can be applied rather conveniently to evaluate: 1) the electromagnetic fields generated by current pulses propagating along overhead power lines; and 2) the electromagnetic fields generated by vertical conductors and towers during lightning strikes.
15.	Daroui, Danesh, et al. (författare) PEEC-based Simulations Using Iterative Method and Regularization Technique for Power Electronic Applications 2014 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 56:6, s. 1448-1456 Tidskriftsartikel (refereegranskat)abstract The partial element equivalent circuit (PEEC) method has been widely used in different industrial and scientific fields for electromagnetic analysis. PEEC-based solvers have been optimized and accelerated in order to be able to solve larger and more complex problems that arise in industry. In power electronic system simulations, PEEC models are often simplified by neglecting electric field couplings and using quasi-static model. The simplified system can be further accelerated using reluctance technique and then sparsified up to high levels without degrading the accuracy of the solution. In previous work, the sparse system was solved using sparse direct solution, while in this study, an iterative approach is employed which resulted in lower time complexity of the solution. However, since matrices achieved from PEEC equations are severely ill-conditioned, regularization techniques need to be applied to avoid numerical instabilities. The regularization is done mathematically and can be interpreted as adding a frequency-dependent pseudocapacitor to each node in the PEEC model. Because the pseudocapacitors are frequency dependent, hence frequencies close to dc are not covered in this study and have left as future work. The new sparse and regularized system can then be solved using a Schur complement technique together with iterative solvers with a novel preconditioning approach.
16.	De Lauretis, Maria, et al. (författare) A Delay-Rational Model of Lossy Multiconductor Transmission Lines with Frequency Independent Per-Unit-Length Parameters 2015 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 57:5, s. 1235-1245 Tidskriftsartikel (refereegranskat)abstract Cables, printed circuit boards, and VLSI interconnects are commonly modelled as multiconductor transmission lines. Models of electrically long transmission lines are memory and time consuming. In this paper, a robust and efficient algorithmfor the generation of a delay-based model is presented. The impedance representation via the open-end matrix Z is analyzed. In particular, the rational formulation of Z in terms of poles and residues is exploited for both lossless and lossy cases. The delaysof the lines are identified, and explicitly incorporated into the model. A model order reduction of the system is automatically performed, since only a limited number of poles and residues are included in the rational part of the model, whereas the highfrequency behaviour is captured by means of closed expressions that accounts for the delays. The proposed method is applied to two relevant examples and validated through the comparison with reference methods. The time domain solver is found to be more accurate and significantly faster than the one obtained froma pure-rational model.
17.	De Lauretis, Maria, et al. (författare) A SPICE Realization of the Delay-Rational Green's-Function-based Method for Multiconductor Transmission Lines 2016 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 58:4, s. 1158-1168 Tidskriftsartikel (refereegranskat)abstract Virtual prototyping has become an unavoidable step in the design of electrical and electronic systems.In this context, time-domain models have to be efficiently embedded in circuit simulator environments, such as SPICE-like transient simulators.Recently, the authors focused on the interconnections, modeled using the multiconductor transmission lines theory, and a Delay-Rational method has been developed, based on Green's functions and line-delay extraction.This work presents a SPICE synthesis of the Delay-Rational method previously developed by the authors.The solution was tested for three transmission lines with frequency-independent per-unit-length parameters.We compared the SPICE results of the Delay-Rational method with those of two standard techniques: one based on a pure rational model and one based on the inverse fast Fourier transform.The time-domain simulations in SPICE of the Delay-Rational method show both accuracy and a remarkable reduction in the number of components used with respect to a purely rational approach, by virtue of the delay extraction.
18.	Di Murro, Francesca, et al. (författare) Efficient Computation of Partial Elements in the Full-Wave Surface-PEEC Method 2021 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : IEEE. - 0018-9375 .- 1558-187X. ; 63:4, s. 1189-1201 Tidskriftsartikel (refereegranskat)abstract The partial element equivalent circuit (PEEC) method provides an electromagnetic model of interconnections and packaging structures in terms of standard circuit elements. The surface-based PEEC (S-PEEC) formulation can reduce the number of unknowns compared to the standard volume-based PEEC (V-PEEC) method. This reduction is of particular use in the case of high-speed circuits and high-switching power electronics, where the bandwidth extends from low frequencies to the GHz range. In this article, the S-PEEC formulation is revised and cast in a matrix form. The main novelty is that the interaction integrals involving the curl of the magnetic and electric vector potentials are computed through the Taylor series expansion of the full-wave Green’s function, leading to analytical forms that are rigorously derived. Therefore, the numerical integration is avoided, with a consequent reduction of the computation time. The proposed formulas are studied in terms of the frequency, size of the mesh, and distance between the basis function domains. Three examples are presented, confirming the accuracy of the proposed method compared to the V-PEEC method and surface-based numerical methods from literature.
19.	Edelvik, Fredrik (författare) A New Technique for Accurate and Stable Modeling of Arbitrarily Oriented Thin Wires in the FDTD Method 2003 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 45, s. 416-423 Tidskriftsartikel (refereegranskat)
20.	Ekman, Jonas, et al. (författare) Impact of partial element accuracy on PEEC model stability 2006 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 48:1, s. 19-32 Tidskriftsartikel (refereegranskat)
21.	Eriksson, Klas, 1983, et al. (författare) Suppression of Parasitic Substrate Modes in Multilayer Integrated Circuits 2015 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 57:3, s. 591-594 Tidskriftsartikel (refereegranskat)abstract Integrated circuits (ICs) with multilayer backend process and a large front-side ground plane support the propagation of parasitic substrate modes. These modes resonate at frequencies that typically are within the bandwidth of circuits operating close to and in the submillimeter-wave range, i.e., beyond 300 GHz. The resonances cause unwanted coupling and feedback, which result in circuit instability and degraded performance for circuits operating in the range of these resonances. A common method to suppress these modes from propagating is to use numerous through-wafer vias distributed over the entire circuit. In this letter, we present a study of substrate modes in multilayer ICs with thin-film microstrip interconnects at 125-330 GHz. We show that a doped Si carrier underneath the circuit effectively eliminates the effect of substrate modes on the circuit functionality. This method requires no backside processed through-wafer vias and no backside metallization.
22.	Ferrer Coll, Javier, 1983-, et al. (författare) Radio-Frequency Electromagnetic Characterization in Factory Automation Infrastructures 2012 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 54:3, s. 708-711 Tidskriftsartikel (refereegranskat)abstract In recent years, industrial wireless applications have emerged rapidly. The use of short-range radio communication systems in factories increases the flexibility in industrial processes by reducing the use of cables. However, the technological challenges involved in wireless communication in industrial environments are not trivial; they result in disadvantages with respect to reliability and security because of electromagnetic interferences. To gain an understanding of the performance limits of these wireless applications, knowing the characteristics of these environments is essential. In this approach, amplitude probability distribution (APD) and rms delay spread measurements have been used to perform electromagnetic site surveys in three factory automation infrastructures.
23.	Fors, Karina, et al. (författare) A simple measurement method to derive the impulsiveness correction factor for communication performance estimation 2013 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : IEEE. - 0018-9375 .- 1558-187X. ; 55:5, s. 834-841 Tidskriftsartikel (refereegranskat)abstract Today, no simple methods are available for measurements of interference signals that give a proper indication of the impact in terms of the bit error probability (BEP) on a digital radio receiver. Such measure should quantify the corresponding impact and the measurements should be relatively easy to perform. By only using the root mean square (RMS) value of the interference average power the BEP can be underestimated with several magnitudes. To address this problem, an impulsiveness correction factor (ICF) has earlier been proposed to adjust for these errors. The ICF opens up for considerably more accurate BEP estimations whereas the simplicity in the calculations is maintained. However, how to determine the ICF for an arbitrary interference source through measurements has not earlier been known. In this paper, we show that the ICF can be obtained in two alternative ways. One way is to use the measured amplitude probability distribution (APD). The other way is to use the peak- and RMS values from standard measurement detectors. Both methods take the interference waveform properties into consideration and the BEP can thus be more accurately estimated.
24.	Glazunov, Andrés Alayón, et al. (författare) Probability Distribution Function of the Electric Field Strength From a CW IEMI Source 2014 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 56:6, s. 1550-1558 Tidskriftsartikel (refereegranskat)abstract A statistical method for predicting the vulnerability of a target, i.e., critical equipment, located inside a building subject to a radiated Intentional Electromagnetic Interference (IEMI) source outside a building, has been devised. Combining probability density functions of small-and large-scale fluctuations of the electric field strength results in a Suzuki distributed electric field strength impinging at the equipment. Specifying the susceptibility level or the critical electric field strength of the target, the vulnerability of a target is evaluated as a function of the distance between source and target, taking into account losses from in and outside the building. Vulnerability isocontours defined as lines of constant probability of exceeding the susceptibility level are presented for a generic, continuous wave power source in a scenario emulating a dense urban microcell propagation environment. A comparison of the vulnerabilities predicted based on the Suzuki and the Log-normal distributions are also been provided for the same scenario. The proposed method provides estimates of critical distances of radiated IEMI attacks and may have use when deciding on the perimeter defense of a facility.
25.	Gruden, Mathias, et al. (författare) Large Ad Hoc Shielded Room with Removable Mode Stirrer for Mobile Phone Antenna Tests 2013 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 55:1, s. 21-27 Tidskriftsartikel (refereegranskat)abstract Reverberation chambers (RC) are widely used for measuring antenna performance and parameters for MIMO systems. RCs for mobile phone antenna tests are often specially designed for this purpose. The lowest frequency of operation of an RC is decided by its size. With a trend of lower frequency bands being allocated for mobile phones, the minimum size of RCs for mobile phone antenna tests increases, and is approaching the size of a normal room. At the same time, many large shielded rooms are already in use for various electrical measurements. In this paper, a standard shielded room designed for EMC testing is used as an RC for mobile phone antenna tests. To complete the RC, a large mode stirrer is built. The fact that the room is also used for other tests requires a detachable, foldable, and lightweight stirrer design. Therefore, metal meshes are evaluated for the design of the mode stirrer. The performance of the used room is verified by standard tests for RCs, and it is verified that it is possible to measure antennas from about 400 MHz up to 4 GHz with good accuracy. The size of the room also enables measurements including humans carrying mobile phones or body area networks.
26.	Guo, Jun, et al. (författare) On the Modeling of Non-Vertical Risers in the Interaction of Electromagnetic Fields With Overhead Lines 2019 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9375 .- 1558-187X. ; 61:3, s. 631-636 Tidskriftsartikel (refereegranskat)abstract This paper proposes a simple method to take into account non-vertical risers through an equivalent partial inductance. The proposed approach was validated considering several examples and taking as reference full-wave results obtained using a numerical electromagnetics code numerical electromagnetics code (NEC)-4.
27.	Hartman, Andreas, et al. (författare) Bandlimited Distortionless Material Design by an Approximation of the Heaviside Condition 2020 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : IEEE. - 0018-9375 .- 1558-187X. ; 62:2, s. 532-541 Tidskriftsartikel (refereegranskat)abstract The distortionless propagation of signals in a medium offers a way to preserve the signal integrity. There exists a condition for distortionless propagation on a transmission line known as the Heaviside condition. This paper proposes the use of the Heaviside condition to characterize and design magnetodielectric materials that provide distortionless propagation in a specified finite frequency band. Plane wave propagation in a magneto-dielectric material is modeled by a transmission line model, thereby assuming TEM mode propagation. Then, the Heaviside condition is employed to derive the frequency-dependent permittivity and permeability functions of the material in rational form, so they satisfy the condition in a specified frequency interval. A procedure to design such materials is described. A numerical example of the design process is provided and an illustration of the effectiveness of modeled material in fulfilling the Heaviside condition in a specified frequency interval both in the time and frequency domains is given, indicating the validity of the approximation. The design procedure areas such a suitable preliminary design guide for deriving a realizable description of a magneto-dielectric, exhibiting the distortionless property in the desired frequency interval, with certain specified requirements put on the loss, or the permeability and permittivity values satisfied. The obtained results may initiate further investigations into the bandwidth restrictions of the approximation, on closed-form design solutions, and the practical realization of such materials.
28.	Hartman, Andreas, et al. (författare) Partial Element Equivalent Circuit Models of Three-Dimensional Geometries Including Anisotropic Dielectrics 2018 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9375 .- 1558-187X. ; 60:3, s. 696-704 Tidskriftsartikel (refereegranskat)abstract During recent years anisotropic materials have received an increasing interest and found important applications in the field of shielding and antennas. The anisotropy may be due to intrinsic properties, or as a consequence of mixing. Intentionally or not, the anisotropy impacts the electromagnetic (EM) behavior of a system. Therefore, it is desirable to be able to incorporate the anisotropic effects in an EM model, to allow design tasks and analysis. In this paper, the partial element equivalent circuit (PEEC) formulation is extended to handle nondispersive linear anisotropic dielectrics. The anisotropic dielectric PEEC cell is derived and the resulting PEEC equations are developed into a descriptor system form, which is well suited for implementation in SPICE-like solvers, and for reduction by model-order reduction techniques. A verification of the model is given by a numerical example of a patch antenna situated on an anisotropic substrate and the results are in good agreement with a finite-difference time-domain implementation. The proposed PEEC model is of interest for further work, i.e., in the modeling of setups involving mixtures of materials, with an orientational alignment, and engineered materials, encountered in different EM compatibility applications.
29.	Javor, Vesna, et al. (författare) Analytical Representation of Measured Lightning Currents and Its Application to Electromagnetic Field Estimation 2018 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : IEEE. - 0018-9375 .- 1558-187X. ; 60:5, s. 1415-1426 Tidskriftsartikel (refereegranskat)abstract Lightning discharge currents waveshapes and their derivatives with multiple peaks are measured in artificially triggered lightning experiments and at instrumented tall towers. Such waveshapes are represented in this paper by the N-peaked analytically extended function (NP-AEF) and Marquardt least-squares method is applied for the estimation of its nonlinear parameters. Typical channel-base currents of the first negative, subsequent negative strokes, and positive strokes, based on comprehensive measurements by Berger et al. at Monte San Salvatore in Switzerland, are approximated by NP-AEFs and used in the computation of lightning electromagnetic fields. A new attenuation factor introducing nonlinear current attenuation along the channel is applied within the modified transmission line model (MTLSIN). A lightning return stroke is assumed to have a vertical discharge channel at the perfectly conducting ground. In order to validate this model, calculated lightning electromagnetic fields are compared with the typical, as measured by Lin et al. at various distances from the discharges. Lightning currents and their derivatives measured at the tall towers are also approximated by NP-AEFs. For the measured artificially triggered lightning currents, MTLSIN is applied for the calculation of their electromagnetic fields. These are compared with the measured fields of specific lightning strokes, so as to results of other models.
30.	Johansson, Markus, 1978, et al. (författare) Source Modeling using Phaseless Low-Frequency Near-Field Measurements 2012 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 54:3, s. 613-624 Tidskriftsartikel (refereegranskat)abstract Field measurements of both amplitude and phase generally are more complicated and require more expensive equipment than amplitude-only measurements. Phase retrieval from measured phaseless field data is, therefore, of interest for source modeling in dosimetry applications, electromagnetic compatibility investigations, near-field to far-field transformations and antenna diagnostics. We here present a phase-retrieval method that uses an optimization algorithm based on the phase angle gradients of a functional. Numerical test cases have shown that the method is working for different initial phase distributions as well as different placements of the source. The method also works well for a test case with measured 50 Hz magnetic flux density from a transformer. The obtained phase angles on a measurement plane in front of the transformer gave calculated field amplitudes on other measurement planes that agree well with measured field. The ratios between the largest amplitude difference and the largest measured amplitude for the three Cartesian magnetic flux density components, for one of the planes, are for example 6.62%, 9.51% and 6.40%.
31.	Karandikar, Yogesh, 1982, et al. (författare) Mode densities in rectangular, cylindrical and spherical cavities in application to the reverberation chamber 2009 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 51:4, s. 1044-1046 Tidskriftsartikel (refereegranskat)
32.	Khan, Qazi Mashaal, 1992, et al. (författare) Validation of IC Conducted Emission and Immunity Models Including Aging and Thermal Stress 2023 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 65:3, s. 780-793 Tidskriftsartikel (refereegranskat)abstract Environmental factors, such as aging and thermal stress, can seriously impact the electromagnetic compatibility behavior of an integrated circuit (IC). The standardized IC emission model for conducted emission (ICEM-CE) and IC immunity model for conducted immunity (ICIM-CI) can be used in industry to predict electromagnetic behavior at the IC and the printed circuit board level. However, these do not take into account the effect of aging and extreme temperature variations. In this article, a custom IC designed in silicon-on-insulator technology, containing several independent analog blocks, is used to characterize the influence of aging and temperature on conducted emission and immunity through measurements and transistor-level simulations. The highly accelerated temperature and humidity stress test (HAST) was performed to evaluate aging and its influence on IC parameters. The results show that the passive distribution network is only influenced by thermal stress and not HAST aging. The latter mainly affects the active elements in the IC and reduces the conducted emission and immunity levels through intrinsic permanent degradation mechanisms. Furthermore, thermal stress mainly causes drifts in the transistor characteristics (such as threshold voltage and effective mobility), which affect the conducted emission and immunity levels and resulting in soft failures. All drifts/tolerances collected from measurements and simulations are characterized in a way that makes it possible to include them in potential future versions of the ICEM-CE and ICIM-CI standards.
33.	Koohestani, M., et al. (författare) Frequency Selective Surfaces for Electromagnetic Shielding of Pocket-Sized Transceivers 2020 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 62:6, s. 2785-2792 Tidskriftsartikel (refereegranskat)abstract This article presents a comprehensive study of the use of small-sized frequency selective surfaces (FSS) to selectively shield pocket-sized devices against EM disturbances. A typical use case is to protect a 2.4-GHz transceiver (e.g. WiFi/Bluetooth) against ISM/GSM disturbances (around 868/915 MHz), using an 8.2 – 4.1 cm FSS structure. A detailed comparison is drawn between results in real and emulated far-fields for different FSS-to-antenna distances (5 and 25 mm), which is further confirmed by emission measurements employing an open transverse electromagnetic cell. Results demonstrate, in line with full-wave simulations including calculated Poynting integrals, that such a FSS can effectively reduce power by about 5 dB in the stopband, while providing no attenuation in the passband and is small enough for an easy integration. Moreover, it is shown that the farther the FSS from the antenna, the closer the results to a no-FSS scenario. This provides an insight to reconsider FSSs for the shielding of mobile and/or smart devices.
34.	Kovačević-Badstüebner, Ivana, et al. (författare) Accurate Calculation of Partial Inductances for the Orthogonal PEEC Formulation 2021 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : IEEE. - 0018-9375 .- 1558-187X. ; 63:1, s. 82-92 Tidskriftsartikel (refereegranskat)abstract The Partial Element Equivalent Circuit (PEEC) method is promising numerical technique for three-dimension electromagnetic modeling across various application fields. In the framework of the PEEC method, the partial elements modeling the magnetic and electric field coupling between elementary volumes and surfaces are computed by double-folded volume and surface integrals. Assuming the quasi-static hypothesis and an orthogonal mesh, the integrals have been computed by the analytical formulas derived in literature, which significantly reduces the computational time in comparison to the numerical integration. However, the existing analytical formulas are affected by significant numerical errors for certain PEEC structural mesh necessary to model the skin and proximity effects with a higher accuracy. To utilize the full potential of the PEEC method, the calculation of partial elements has to be carefully addressed, which has not been investigated in a comprehensive way so far. Accordingly, this paper presents a systematic accuracy analysis of the existing closed-form analytical formulas and methods for calculating the self and mutual inductances between two rectangular conductors. Additionally, a new strategy to select a proper analytical formula depending on the dimensions and positions of two conductors is proposed, which allows the mutual inductance extraction with a relative error of less than 0.1 % . The new method is systematically validated on examples of 3-D dense PEEC systems using the quadruple precision arithmetic as reference.
35.	Larsson, Anders, et al. (författare) Radiated electric field strength from high-power microwave systems 2008 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 50:3, s. 758-761 Tidskriftsartikel (refereegranskat)abstract Intentional electromagnetic interference (IEMI) is an emerging threat and a new electromagnetic environment that has to be considered in the mitigation of electromagnetic compatibility problems. This paper presents an attempt to estimate the upper limitations of IEMI systems based on high-power microwave devices. The upper limit of transmitted electromagnetic wave power is basically set by the microwave breakdown event. The estimate includes the properties of the electromagnetic wave propagation from the generation of the wave to the possible target.
36.	Li, Bing, et al. (författare) Effect of Periodicity in Frequency Responses of Networks From Conducted EMI 2017 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9375 .- 1558-187X. ; 59:6, s. 1897-1905 Tidskriftsartikel (refereegranskat)abstract In this paper, we consider different types of networks, and investigate the characteristics of the frequency responses of loads, which are distributed in the networks. Without loss of generality, both frequency-independent and frequency-dependent loads are discussed, respectively. Beginning with a transmission-line (TL) network with frequency-independent loads, via the TL theory and Baum-Liu-Tesche equation, we demonstrate that the frequency responses are periodic in the frequency domain, where the periodicity is derived and verified. Subsequently, our study is extended to the complex networks that consist of multiple junctions and branches. By using the statistical method, we generate random loads with different attributes, i.e., resistive, inductive, or capacitive, and mainly study the effect of the number of branches and junctions on the frequency response of targeted load in various networks. From the perspective of protections for the targeted load in networks, results indicate that, for lossless and good dielectric (i.e., low-loss) media, it is crucial to consider the frequency responses at the critical frequencies in a periodical manner, rather than at a single frequency. Furthermore, it is worth noting that, the frequency response of targeted load behaves differently when varying the attributes of other loads in the network. The variation of network topology, i.e., increasing the number of junctions or branches, also influences the frequency response.
37.	Liu, Yaqing, et al. (författare) An Improved Transmission-Line Model of Grounding System 2001 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9375 .- 1558-187X. ; 43:3, s. 348-355 Tidskriftsartikel (refereegranskat)abstract This paper presents a time-domain transmission line model of grounding system, which includes the mutual electromagnetic coupling between the parts of the grounding structure and the influence of air-earth interface. The model can be used to simulate the transient behavior of the grounding system under lightning strike. The simulation results are in good agreement with that of the model based on the solution of full Maxwell's equations. The influence of different parameters, such as the soil relative permittivity /spl epsi//sub /spl tau//, the soil resistivity /spl rho/, and the conductivity and diameter of the conductor, on the transient voltage distribution of the grounding system is investigated. It shows that, among the parameters investigated here, the soil resistivity is the most important parameter that affects the transient response of bare buried conductors. The soil permittivity has very little influence on the transient response of the grounding system when the grounding system is buried in the soil with low resistivity, but have moderate influence in the soil with extremely high resistivity. The conductivity of the conductor and skin effect have practically no influence on the peak transient voltage of the grounding system. Increase in conductor diameter tends to decrease the peak transient voltage. The model presented in this paper is simple, but sufficiently accurate and can be used easily in engineering practice. Since the model is in the time domain, it could be easily coupled to the other time-domain models of nonlinear surge-protection components.
38.	Long, Mengni, et al. (författare) Modeling the Attachment of Lightning Dart and Dart-Stepped Leaders to Grounded Objects 2017 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9375 .- 1558-187X. ; 59:1, s. 128-136 Tidskriftsartikel (refereegranskat)abstract Attachment of downward subsequent dart leaders has been recently proposed as a possible mechanism of lightning damage of wind turbine blades. Since subsequent dart and dart-stepped leaders propagating after the first lightning discharge are one-to-two orders of magnitude faster than downward stepped leaders, the direct evaluation of the dart leader interception by upward connecting leaders from the turbine has not been attempted before. In this paper, the self-consistent leader inception and propagation model SLIM is used to evaluate the lightning attachment process of subsequent dart leaders by accounting the rapid changing electric fields produced by their fast descent toward the ground. For this, an improved evaluation of the charge per unit length required to thermalize the upward connecting leader is derived. The analysis considers upward connecting leaders propagating along the preheated channel of a prior discharge. Three study cases of lightning attachment of dart leaders and dart-stepped leader reported in rocket-triggered lightning experiments are evaluated. It is shown that reasonable predictions of the length, duration, and velocity of positive upward connecting leaders can be obtained with SLIM in agreement with the experimental results. Further research on upward leader discharges necessary to improve the modeling of attachment of dart lightning leaders is discussed.
39.	Long, Mengni, 1987-, et al. (författare) Modeling the Attachment of Lightning Dart and Dart-Stepped Leaders to Grounded Objects 2024 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9375 .- 1558-187X. Tidskriftsartikel (refereegranskat)abstract Attachment of downward subsequent dart leadershas been recently proposed as a possible mechanism of lightningdamage of wind turbine blades. Since subsequent dart and dart-stepped leaders propagating after the first lightning discharge are one-to-two orders of magnitude faster than downward stepped leaders, the direct evaluation of the dart leader interception by upwardconnecting leaders from the turbine has not been attempted before. In this paper, the self-consistent leader inception and propagation model SLIM is used to evaluate the lightning attachmentprocess of subsequent dart leaders by accounting the rapid changingelectric fields produced by their fast descent toward the ground. For this, an improved evaluation of the charge per unit length requiredto thermalize the upward connecting leader is derived. The analysis considers upward connecting leaders propagating along the preheated channel of a prior discharge. Three study cases oflightning attachment of dart leaders and dart-stepped leader reported in rocket-triggered lightning experiments are evaluated. It is shown that reasonable predictions of the length, duration, andvelocity of positive upward connecting leaders can be obtainedwith SLIM in agreement with the experimental results. Furtherresearch on upward leader discharges necessary to improve themodeling of attachment of dart lightning leaders is discussed.
40.	Lundgren, Johan, et al. (författare) Visualization and Reduction of Mutual Coupling between Antennas Installed on a Platform 2022 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9375 .- 1558-187X. ; 64:1, s. 92-101 Tidskriftsartikel (refereegranskat)abstract Mutual coupling, or equivalently, the isolation between antennas, is a key parameter in antenna system design. In this article, the previously defined impedance density is generalized, and it is demonstrated how it can be used to obtain spatial information about the mutual coupling. The generalized impedance density is a real-valued scalar and it can be visualized as a three-dimensional (3-D) density in space. It is shown that there is a strong connection between regions with a positive (negative) generalized impedance density and a decrease (increase) of the coupling when an absorber is placed in that region. This predictive ability is a useful feature, which is tested for three numerical cases. The results are robust to the shape of the platform, and it can be compared across frequencies. By placing absorbers based on the generalized impedance density, it is possible to reduce the required amount of absorbers needed to obtain a certain reduction in mutual coupling. The visualization results and predictions of absorber positions are compared with a Poynting vector based method. Placing absorbers based on the generalized impedance density had a larger impact on the mutual coupling, compared to the predictions with the Poynting vector based method in the investigated cases.
41.	Lundgren, U, et al. (författare) Shielding effectiveness data on commercial thermoplastic materials 2006 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 48:4, s. 766-773 Tidskriftsartikel (refereegranskat)abstract Ten different commercially available conductive thermoplastic materials have been tested for near- and far-field shielding effectiveness (SE). Far-field SE was tested using a modified standard measurement technique to provide results comparable with the company-provided data. Further, housings of different thermoplastic materials were constructed and equipped with an electromagnetic interference (EMI) source to model a realistic near-field SE situation. The SE data up to 1 GHz is presented. Conductive thermoplastic materials with fillings of stainless steel fibers and nickel-coated carbon fibers were the two materials that offer the best far-field shielding performance. For the near-field shielding, two materials with filling of stainless steel fibers were the best performing ones. A thermoplastic with polycarbonate (PC) base and stainless steel content of 1.5 vol% showed the best combined far- and near-field shielding results.
42.	Mahfouz, MHD Zaher, et al. (författare) Measurement and Estimation Methodology for EMC and OTA Testing in the VIRC 2023 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 65:1, s. 3-16 Tidskriftsartikel (refereegranskat)abstract In recent years, promising results have been reported with the vibrating intrinsic reverberation chamber (VIRC) combining performance and cost-efficiency for electromagnetic compatibility (EMC) measurements. This also makes it a potentially attractive solution for over-the-air (OTA) testing, which is yet to be investigated. Therefore, this article proposes the first systematic and thorough methodology to characterize the VIRC for use in EMC and OTA testing of wireless baseband algorithms of narrow-band single-input single-output channels. This methodology has been developed to measure and estimate the channel first- and second-order temporal and spectral characteristics taking into consideration the effect of different carrier frequencies, rotational speeds of VIRC motors, and loading conditions. It is then applied to a channel setup inside a VIRC for a preliminary investigation before the VIRC itself is fully characterized. It is shown that mounting an absorber in a specific location on the hatch significantly improves the rejection rate of the chi-squared goodness-of-fit test for Rician distribution without increasing the K-factor above -10 dB over the frequency range 755-2740 MHz in the VIRC under investigation. However, the proposed methodology has been devised to be universal to any reverberation chamber, and the obtained results can be used to improve EMC testing due to the better understanding of the unique VIRC environment.
43.	Malmström, Johan, et al. (författare) On Mutual Coupling and Coupling Paths between Antennas Using the Reaction Theorem 2018 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9375 .- 1558-187X. ; 60:6, s. 2037-2040 Tidskriftsartikel (refereegranskat)abstract The reaction theorem is applied to antenna coupling problems. It is shown that the reaction theorem can be used to calculate the mutual impedance between antennas, when the electromagnetic fields are known on a plane that separates the two antennas in two disjoint regions. We also show that coupling paths between the antennas can be visualized on the separation plane, by using intermediate results from the reaction theorem. The coupling paths are visualized based on the fields generated by each of the two antennas, and only take into account the energy that is actually transfered between the antennas. The visualization of coupling paths is useful for understanding how the coupling between the antennas is distributed in space.
44.	Mazloom, Ziya, et al. (författare) A Method for Interfacing Lumped-Circuit Models and Transmission-Line System Models With Application to Railways 2009 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 51:3, s. 833-841 Tidskriftsartikel (refereegranskat)abstract Transient analysis of lossy multiconductor transmission lines (MTL) have been studied using the finite difference time domain (FDTD) method with lumped loads/devices connected at line terminations. In electrified railway networks series and shunt devices (whose circuit models derived either from experiments/borrowed off the shelf), e.g., transformers, converters, switchgear, signal equipments, etc., are found distributed along the MTL system. To simulate such railway systems involving both transmission lines (TL) and lumped circuits, an interface technique between TL system solved using FDTD and all the lumped circuits solved using ATP/EMTP software (circuit solver) is proposed. This sufficiently accurate method is simple to apply as only instantaneous voltages and currents are transmitted between standalone FDTD routine and circuit solver. Moreover, the user avoids coding complex circuit models within the FDTD, while at the same time efficiently uses the potential of accurate frequency dependant loss models (nonexistent in circuit software) coded in FDTD. The technique is applied on typical electrified railway systems to demonstrate how traction transformers, track circuits, and line interconnections affect the propagating voltages and currents. The method could be beneficial for transient protection and insulation coordination studies in electrified railway systems.
45.	Mazloom, Ziya, et al. (författare) Indirect Lightning-Induced Voltages Along a Railway Catenary-Track Multiconductor Transmission-Line System With Lumped Components 2011 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 53:2, s. 537-539 Tidskriftsartikel (refereegranskat)abstract Transients caused by field-to-wire coupling due to lightning strikes in the vicinity of multiconductor transmission lines (TL) have been widely studied. In those studies, the lines represent single overhead lines, power lines, and the like with lumped loads/devices at line terminations. In electrified railway power systems, series or shunt devices, such as transformers, converters, switchgear, and signal equipments, are distributed along the TL system. In this paper, the indirect lightning effects on a typical railway catenary-track multiconductor TL system with lumped components, namely, booster and auto transformers (BT and AT systems), and track circuits, are studied. It is found that the induced voltage wave shapes and amplitudes at any point along the line are dominated by BT or AT system type, and that the voltages appearing across AT windings are higher than for the corresponding BT windings. However, the induced voltages across the track circuits are less dependent on system type and most affected by the introduction of components.
46.	Mazloom, Z., et al. (författare) Modeling Indirect Lightning Strikes for Railway Systems With Lumped Components and Nonlinear Effects 2011 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 53:1, s. 249-252 Tidskriftsartikel (refereegranskat)abstract Induced voltages due to lightning strikes along multiconductor transmission line (MTL) systems terminated with different loads at line ends have been widely studied by solving telegraphers' equations using the finite-difference time-domain method. However, MTL systems with lumped series and shunt-connected devices/components along the lines have not attracted much attention. There are methods available for introducing lumped components along MTL systems. In this paper, a method previously developed by the authors will be used to determine induced voltages across transformers connected to the catenary wire and track-circuit relay units along the MTL system representative of a Swedish single-track railway system for the case of indirect lightning strikes. Nonlinearities like soil ionization and insulator flashovers are also considered. It is found that both the nonlinearities and lumped components together dominate the induced-voltage amplitude and wave shapes across devices/components.
47.	Midya, Surajit, et al. (författare) DC Component From Pantograph Arcing in AC Traction System : Influencing Parameters, Impact, and Mitigation Techniques 2011 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - : IEEE conference proceedings. - 0018-9375 .- 1558-187X. ; 53:1, s. 18-27 Tidskriftsartikel (refereegranskat)abstract Pantograph arcing in ac traction system generates transients, and causes asymmetries and distortion in supply voltage and current waveforms. These asymmetric voltage and current lead to a net dc component and harmonics that propagate within the traction power and signalling system and cause electromagnetic interference. This problem is enhanced during winter because of the layer of ice/snow on the overhead contact wire. The sliding contact becomes poor and a visible arc moves along with the pantograph. In this paper, it is shown how different parameters like traction current, line speed, power factor, and supply voltage influence the arcing, its characteristics, and the dc components. It is shown that the dc current component increases with increasing train speed and traction current, and reduces at a lower power factor. It is also discussed how the presence of an ice layer influences the arcing and the dc components. It is found that running the trains below the normal operating power factors is an effective choice to mitigate this problem. The findings presented in this paper could be beneficial to estimate the probable limit of the dc component at the planning stage so that proper precautions can be taken at the design stage itself.
48.	Månsson, Daniel, et al. (författare) Comments on "Linear and Nonlinear Filters Suppressing UWB Pulses" 2005 Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 47:3, s. 671-672 Tidskriftsartikel (refereegranskat)abstract In a recently presented paper, different surge protective devices' response to conducted UWB pulses are investigated. However, it is shown here that some of the results for varistors presented in that paper are due only to the packaging and not to the surge protective element in itself.
49.	Månsson, Daniel, et al. (författare) Methodology for Classifying Facilities with respect to Intentional EMI 2009 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 51:1, s. 46-52 Tidskriftsartikel (refereegranskat)abstract It is argued that it is the intent behind the electromagnetic interference in intentional electromagnetic interference (IEMI) that causes problems to large distributed systems and facilities even if they are designed by traditional zoning concept rules. Hardening such facilities against IEMI requires a correspondence between the electromagnetic zone boundary and the physical access control boundary. The three characteristics of a facility, the accessibility, susceptibility, and consequence, are discussed in the context of vulnerability to IEMI. A methodology for classification of facilities
50.	Månsson, Daniel, et al. (författare) Propagation of UWB Transients in Low-Voltage Installation Power Cables 2007 Ingår i: IEEE transactions on electromagnetic compatibility (Print). - 0018-9375 .- 1558-187X. ; 49:3, s. 585-592 Tidskriftsartikel (refereegranskat)abstract This paper investigates the propagation of subnanosecond rise time (ultra wideband) voltage transients in low-voltage installation power cables. Experimental results are compared to simulations. It is concluded that the main mode of propagation of differentially injected transients in low-voltage installation power cables is transverse electromagnetic mode. Also, such transients would spread relatively unattenuated to any load or junction in the power system, received power primarily only limited by the impedance mismatches causing reflections. The effects of different types of bends in the cable have been studied. The study was conducted as a part of an assessment of the susceptibility of civilian facilities to intentional electromagnetic interference.

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