Showing papers in "IEEE Transactions on Electromagnetic Compatibility in 2014"
TL;DR: In this article, an efficient approach to achieve the shielding effectiveness (SE) by using a frequency-selective surface (FSS) is presented, which consists of cross dipoles and rings printed on the opposite sides of a single-layer FR-4 substrate, exhibits a wide, 7.5GHz stopband to provide simultaneous shielding in both X and Ka-bands.
Abstract: An efficient approach to achieve the shielding effectiveness (SE) by using a frequency-selective surface (FSS) is presented. This FSS, which consists of cross dipoles and rings printed on the opposite sides of a single-layer FR-4 substrate, exhibits a wide, 7.5-GHz stopband to provide simultaneous shielding in both X- and Ka-bands. Experimental results confirm SE of the prototype over an ultra-wide band with more than 20-dB measured attenuation. The design is compact and suitable to provide shielding against the radiation interference caused by license-free and other radio systems.
190 citations
TL;DR: In this article, a review and comparison of different models representing the frequency dependence of the soil electrical parameters (conductivity and permittivity) are presented in terms of curve-fit expressions for the soil conductivity and relative permittivities, which are based on experimental data.
Abstract: We present a review and comparison of different models representing the frequency dependence of the soil electrical parameters (conductivity and permittivity). These models are expressed in terms of curve-fit expressions for the soil conductivity and relative permittivity, which are based on experimental data. Six available models/expressions are discussed and compared making reference to two sets of experimental data. It is shown that the soil models by Scott, Smith-Longmire, Messier, and Visacro-Alipio predict overall similar results, which are in reasonable agreement with both sets of experimental data. Differences between the soil models are found to be more significant at high frequencies and for low-resistivity soils. The causality of the considered models is tested using the Kramers-Kronig relationships. It is shown that the models/expressions of Smith-Longmire, Messier, and Portela satisfy the Kramers-Kronig relationships and thus provide causal results. The soil models are applied to the analysis of grounding systems subject to a lightning current. A full-wave computational model is adopted for the analysis. The analysis is performed considering two cases: 1) a simple horizontal grounding electrode, and 2) a realistic grounding system of a wind turbine. Two current waveforms associated with typical first and subsequent return strokes are adopted for the representation of the incident lightning current. In agreement with recent studies, simulations show that the frequency dependence of the soil parameters results in a decrease of the potential of the grounding electrode, with respect to the case where the parameters are assumed to be constant. It is found that the models/expressions by Scott, Smith-Longmire, Messier, and Visacro-Alipio predict similar levels of decrease, which vary from about 2% (ρLV = 20 Ω·m and first stroke) up to 45% (ρLV = 10 000 Ω·m and subsequent stroke). On the other hand, the models of Portela and Visacro-Portela predict significantly larger levels of the decrease, especially for very high resistivity soils. Furthermore, in the case of a high resistivity soil (10 000 Ω·m), the Visacro-Alipio expression predicts a longer risetime for the grounding potential rise, compared to the predictions of Scott, Smith-Longmire, and Messier models.
166 citations
TL;DR: In this article, an original semitheoretical causal model was developed to describe the frequency dependence of electrical parameters of soil in the representative frequency range of lightning currents, based on the measured low-frequency soil resistivity, can be promptly applied to general soils in practical problems.
Abstract: An original semitheoretical causal model was developed to describe the frequency dependence of electrical parameters of soil in the representative frequency range of lightning currents. The expressions of such model, based simply on the measured low-frequency soil resistivity, can be promptly applied to general soils in practical problems. The model allows the user to adopt different levels of conservativeness to take the dispersion of the frequency dependence of soil and eventual uncertainties into account. The comparison of experimental results and those provided by this model denoted its consistency.
157 citations
TL;DR: In this paper, a comparative study of multilayer graphene nanoribbon (MLGNR) interconnects with side contacts with respect to their distributed parameters and transmission characteristics is performed based on an equivalent single-conductor (ESC) model.
Abstract: Based on an equivalent single-conductor (ESC) model of multilayer graphene nanoribbon (MLGNR) interconnects with side contacts, comparative study on their distributed parameters and transmission characteristics is performed in this paper. It is found that the number of conducting channels of a metallic MLGNR interconnect is the linear function of its width and Fermi energy, which can be described by an analytical equation. Its equivalent inductance and capacitance in the ESC model can also be characterized by a set of closed-form equations. Furthermore, according to the ITRS projection, transmission performance of the MLGNR interconnects with different contacts are predicted and compared with their Cu and carbon nanotube counterparts at different technology nodes. Also, some numerical results prove that MLGNR interconnects can provide better performance than Cu wires in particular at intermediate level. Even with the maximum crosstalk impacts considered, the advantage of MLGNR interconnects over Cu wires can still be kept.
112 citations
TL;DR: In this article, a radiated two-stage (RTS) test method for LTE MIMO UE test is presented, which applies an invert calibration matrix to the input signal of the throughput test, which eliminates the problems of connecting an RF cable directly to the DUT receiver.
Abstract: Two-stage method for long-term-evolution (LTE) multiple-input-multiple-output (MIMO) wireless user equipment (UE) performance evaluation is one of the methods proposed for standard organizations. However, the conducted two-stage method has been challenged for its lack of support for “over-the-air” (OTA) as well as for its negligence of the self-interference in the device under test (DUT) in the throughput test. Self-interference in DUT such as cell phones could significantly reduce receiver sensitivity, thus, if not properly included in the test setup, could affect the test accuracy. In order to solve the problems, a radiated two-stage (RTS) test method for LTE MIMO UE test is presented in this paper. By applying an invert calibration matrix to the input signal of the throughput test, the proposed method performs OTA second-stage test, which eliminates the problems of connecting an RF cable directly to the DUT receiver. The RTS OTA MIMO test method can be executed in a standard single-input-single-output anechoic chamber, reduces overall system cost, and offers high reliability and repeatability. Meanwhile, the measurement provides extensive subcomponent-level performance information and makes it an ideal solution for both research and development (R&D) and certification test.
106 citations
TL;DR: It is shown that electromagnetic information leakage from modern laptops and desktops (with no peripherals attached) is indeed possible and is relatively easy to achieve and how activity levels and data values used in accessing different parts of the memory subsystem affect the transmission distance.
Abstract: This paper shows that electromagnetic (EM) information leakage from modern laptops and desktops (with no peripherals attached) is indeed possible and is relatively easy to achieve. The experiments are performed on three laptop systems and one desktop system with different processors (Intel Centrino, Core 2, Core i7, and AMD Turion), and show that both active (program deliberately tries to cause emanations at a particular frequency) and passive (emanations at different frequencies happen as a result of system activity) EM side-channel attacks are possible on all the systems we tested. Furthermore, this paper shows that EM information leakage can reliably be received at distances that vary from tens of centimeters to several meters including the signals that have propagated through cubicle or structural walls. Finally, this paper shows how activity levels and data values used in accessing different parts of the memory subsystem (off-chip memory and each level of on-chip caches) affect the transmission distance.
103 citations
TL;DR: In this paper, different MCBs with random and spatial arrangements are proposed based on the placements of single and multiwalled carbon nanotubes (SWNTs and MWNTs) in a bundle.
Abstract: Mixed carbon nanotube bundles (MCBs) are considered to be highly potential interconnect solutions in the current nanoscale regime. Different MCBs with random and spatial arrangements are proposed based on the placements of single- and multiwalled carbon nanotubes (CNTs) (SWNTs and MWNTs) in a bundle. Propagation delay and dynamic crosstalk performances are analyzed using the modified equivalent single conductor model of proposed MCB topologies. Encouragingly, a significant reduction in propagation delay and crosstalk delay is observed for a spatial arrangement of an MCB wherein MWNTs are placed peripherally to the centrally located SWNTs. Typically, the average delay with and without crosstalk is improved by 82.8% and 80%, respectively, compared to the MCB having randomly distributed SWNTs and MWNTs.
86 citations
TL;DR: A new procedural method for the systematic analysis of the risk when a specific facility is exposed to an intentional electromagnetic environment (IEME) using statistical-based models for the coupling as well as the system behavior.
Abstract: This paper introduces a new procedural method for the systematic analysis of the risk when a specific facility is exposed to an intentional electromagnetic environment (IEME). The analysis is performed from the viewpoint of the system owner. The exposure of a system to IEME can be described by a set of different scenarios. The method presented in this paper combines characteristics of intentional electromagnetic interference scenarios with susceptibility data of components using statistical-based models for the coupling as well as the system behavior. Within each scenario the coupling to components of the system under assessment is ascertained by an analysis of the electromagnetic topology. The reaction of the system under assessment is modeled by combining the failure probabilities of the components employing the fault tree analysis. The application of a Monte Carlo simulation on the resulting model provides the probability of the top events of the fault trees which are the system level effects or consequences. In a final step, the importance analysis enables the identification of critical elements, e.g., those elements which contribute most to the risk, and therefore starting points for the improvement of the system protection.
81 citations
TL;DR: In this paper, the authors proposed an approach to estimate human exposure to WPT systems operating in the frequency range 0.1-10 MHz with coil diameters up to 150 mm.
Abstract: In this study, human exposure to close-range wireless power transfer (WPT) systems operating in the frequency range 0.1-10 MHz with coil diameters up to 150 mm are investigated. Approximation formulae, which include scaling factors derived from numerical simulations that take variations of complex human anatomies into consideration, are proposed to conservatively estimate human exposure with respect to the most authoritative exposure guidelines. The approximation has been verified for two precommercial prototype WPT systems, the first of which, a 5-W system operating at 100 kHz, has been evaluated in this study; the second system been verified was reported in a separate study and operates at 6.78 MHz with a nominal current of 5.4 A rms. Based on the results obtained, the optimal operational frequency range for WPT with respect to compliance with exposure safety guidelines is revealed to be ca. 1-2.5 MHz. In summary, this study provides novel and insightful information for the design of an exposure-compliant close-range magnetic resonant WPT system.
81 citations
TL;DR: In this paper, the authors proposed a technique to incorporate the lightning arresters in the FDTD-based lightning overvoltage calculations, which can be obtained directly from the data sheets or measured results.
Abstract: To suppress the lightning-induced voltages on a distribution line, lightning arresters and/or overhead shielding wire can be installed, and the effectiveness of these countermeasures are usually studied by simulations. Traditionally, field-to-transmission line coupling techniques based on the distributed-parameter circuit theory are used for the calculation of the lightning-induced voltages. Recently, the finite-difference time-domain (FDTD) method that directly and numerically solves Maxwell's equations was applied to the calculation of the lightning-induced voltages. Compared with the conventional methods, the FDTD-based calculation is advantageous in terms of the modeling of inhomogeneous ground parameters, 3-D structures, and grounding systems. But, in the previous works, the distribution line was simulated simply by a single-phase line. Moreover, the representation of lightning arresters in the FDTD method was not yet established. This paper proposes a technique to incorporate the lightning arresters in the FDTD-based lightning overvoltage calculations. In this technique, the voltage-current relationships of the lightning arresters are represented by piecewise linear curves, which can be obtained directly from the data sheets or measured results. For validation purpose, the lightning-induced voltages on a three-phase distribution line equipped with the lightning arresters and a multipoint-grounded overhead shielding wire are calculated by the proposed method, and the results are compared with those obtained by the conventional method and a very good agreement is found.
76 citations
TL;DR: In this article, the authors provide a method for assessing external lightning protection and earthing designs that may be installed in large-scale solar applications, and the method and models presented in this paper may assist engineers to perform a comparison between the use of isolated and nonisolated lightning protection systems, and second to select suitable surge protection equipment.
Abstract: The development of large-scale photovoltaic (PV) plants in rural areas is constantly increasing. However, the knowledge of performing and installing lightning and surge protection in large-scale PV plants is still premature. The main objective of this paper is to provide a method for assessing the external lightning protection and earthing designs that may be installed in large-scale solar applications. Consequently, the method and models presented in this paper may assist engineers to perform a comparison between the use of isolated and nonisolated lightning protection systems, and second to select suitable surge protection equipment.
TL;DR: It is mathematically demonstrate that the time-of-arrival method can be seen as a subset of EMTR, and it is shown that considering a model in which losses are inverted in the back propagation yields theoretically exact results for the source location.
Abstract: In this paper, we discuss the use of the electromagnetic time reversal (EMTR) method to locate lightning strikes. After a brief description of the EMTR and its application to lightning location, we mathematically demonstrate that the time-of-arrival method can be seen as a subset of EMTR. We propose three different models of backpropagation to address the issue of EMTR not being invariant for lossy media. Two sets of simulations are carried out to evaluate the accuracy of the proposed methods. The first set of simulations is performed using numerically generated fields and the proposed algorithm is shown to give very good results even if the soil is not perfectly conducting. In particular, we show that considering a model in which losses are inverted in the back propagation yields theoretically exact results for the source location. We show also that a lack of access to the complete recorded waveforms may lead to higher location errors, even though the computed errors are found to be within the range of performance of current lightning location systems (LLS). A second set of simulations is performed using the sensor data reported by the Austrian LLS. The locations obtained by way of the proposed EMTR method using only the available sensor data (amplitude, arrival time, and time-to-peak), are observed to be within a few kilometers of the locations supplied by the LLS.
TL;DR: In this paper, an approximate multiconductor transmission-line (MTL) model is developed for predicting the radiated susceptibility of bundles composed of twisted-wire pairs (TWPs) running above a ground plane, and illuminated by a non-uniform electromagnetic field.
Abstract: An approximate multiconductor transmission-line (MTL) model is developed for predicting the radiated susceptibility of bundles composed of twisted-wire pairs (TWPs) running above a ground plane, and illuminated by a nonuniform electromagnetic field. Through the use of averaged per-unit-length parameters and sampling of the incident electromagnetic field, the nonuniform MTL is modeled as an equivalent uniform MTL including common-mode (CM) voltage sources accounting for field-to-wire coupling effects. The proposed model is able to predict CM currents/voltages induced in the terminal loads of every TWP in the bundle. In particular, it is shown that the CM noise significantly differs depending on the position of the considered TWP in the bundle cross section. Comparison of results versus full-wave simulations validates accuracy and computational efficiency of the proposed model.
TL;DR: In this paper, the authors review applications of the FDTD method to LEMP and surge simulations, including 1) lightning electromagnetic fields at close and far distances, 2) lightning surges on overhead power transmission line conductors and towers, 3) lightning spikes on overhead distribution and telecommunication lines.
Abstract: Electromagnetic computation methods (ECMs) have been widely used in analyzing lightning electromagnetic pulses (LEMPs) and lightning-caused surges in various systems. One of the advantages of ECMs, in comparison with circuit simulation methods, is that they allow a self-consistent full-wave solution for both the transient current distribution in a 3-D conductor system and resultant electromagnetic fields, although they are computationally expensive. Among ECMs, the finite-difference time-domain (FDTD) method for solving Maxwell's equations has been most frequently used in LEMP and surge simulations. In this paper, we review applications of the FDTD method to LEMP and surge simulations, including 1) lightning electromagnetic fields at close and far distances, 2) lightning surges on overhead power transmission line conductors and towers, 3) lightning surges on overhead distribution and telecommunication lines, 4) lightning electromagnetic environment in power substations, 5) lightning surges in wind-turbine-generator towers, 6) lightning surges in photovoltaic (PV) arrays, 7) lightning electromagnetic environment in electric vehicles (EVs), 8) lightning electromagnetic environment in airborne vehicles, 9) lightning surges and electromagnetic environment in buildings, and 10) surges on grounding electrodes.
TL;DR: In this article, a simple and fast coating method of honeycomb cores for microwave absorption has been described, and two different thicknesses (5 and 20 mm) coated with thermoplastic resin filled with carbon powder as lossy filler in 5, 10, 15, and 20 wt% have been tested.
Abstract: A simple and fast coating method of honeycomb cores for microwave absorption has been described. The honeycomb cores with two different thicknesses (5 and 20 mm) coated with thermoplastic resin filled with carbon powder as lossy filler in 5, 10, 15, and 20 wt% have been tested for microwave absorption in 2 - 18-GHz frequency range. The 5-mm-thick honeycomb has shown absorption bandwidth of 14 GHz for maximum absorption of -6 dB (75%) with 15 wt%. filler content. However, the percentage of the filler was decreased to 10 wt% in 20-mm-thick honeycomb absorber for maximum absorption over a wide frequency range. The honeycomb sample with 10 wt% filler has bandwidth of 18 GHz for -7 dB (80%) reflection loss. The reflection loss measurements of coated honeycomb cores have also shown that use of E-glass fiber/epoxy composite can enhance the performance of the honeycomb absorber. The combination of a microwave absorbing nanocomposite and the coated honeycombs has been resulted in inferior absorption properties in 2 - 18-GHz frequency range.
TL;DR: In this paper, the authors accurately modeled the crosstalk effects in a CMOS-gate-driven coupled RLC interconnects using the nth power law model and finite-difference time-domain (FDTD) technique.
Abstract: This paper accurately models the crosstalk effects in a CMOS-gate-driven coupled RLC interconnects using the nth power law model and finite-difference time-domain (FDTD) technique. The propagation delay, peak crosstalk voltage, and peak voltage timing on victim line of coupled-multiple lines are observed and compared to HSPICE simulation results for the global interconnect length at 32 nm technology node. The numerical results illustrate that the proposed model accurately estimates the performance parameters of driver interconnect load system. An average error of less than 2% is observed in estimation of peak crosstalk voltage and its timing. The proposed model can be extended for coupled n lines and useful for the evaluation of signal integrity, issues of EMI, and EMC of on-chip interconnects.
TL;DR: In this paper, new shielding parameters are proposed as figures of merit to designate the actual effectiveness of an electromagnetic enclosure in different configurations excited by typical transient electromagnetic threats, and their suitability is tested.
Abstract: The assessment of the shielding effectiveness of enclosures under transient conditions calls for an accurate analysis of fundamental aspects. Stemming from a correct understanding of the coupling mechanism and from a victim point of view, new shielding parameters are proposed as figures of merit to designate the actual effectiveness of an electromagnetic enclosure. Their suitability is tested in different configurations excited by typical transient electromagnetic threats.
TL;DR: In this article, a far-field prediction for EMI testing is achieved using only magnetic near-field on a Huygens's surface using the finite element method (FEM).
Abstract: Far-field prediction for electromagnetic interference (EMI) testing is achieved using only magnetic near-field on a Huygens's surface. The electrical field on the Huygens's surface is calculated from the magnetic near-field using the finite element method (FEM). Two examples are used to verify the proposed method. The first example uses the field radiated by an infinitesimal electric dipole. The calculated results are compared with the analytical solution. In the second example, the calculated results are compared with full-wave simulation results for the radiation of a print circuit board (PCB). The validity of this method when the near-field is high-impedance field is verified as well. Sensitivity of the far field to noise in both magnitude and phase in the near-field data is also investigated. The results indicate that the proposed method is very robust to the random variation of both. The effect of using only four sides of the Huygens's box is investigated as well, revealing that, in some instances, the incomplete Huygens's box can be used to predict the far field well. The proposed method is validated using near-field measurement data taken from a sleeve dipole antenna. The error for the maximum far-field value is in only 1.3 dB.
TL;DR: In this paper, the impact of the frequency dependence of soil resistivity and permittivity on lightning overvoltages induced on overhead lines over lossy ground is investigated, and the Visacro-Alipio expressions were implemented on the hybrid electromagnetic model to take this effect into account.
Abstract: The impact of the frequency dependence of soil resistivity and permittivity on lightning overvoltages induced on overhead lines over lossy ground is investigated. The Visacro-Alipio expressions were implemented on the hybrid electromagnetic model to take this effect into account. Systematic simulations were performed considering representative current waveforms of first and subsequent strokes and different stroke locations near the simulated overhead line. In general, the results indicated that this effect is responsible for a reduction of the induced overvoltage. This reduction increases with increasing soil resistivity and becomes relevant for soil resistivity above 1000 Ω·m.
TL;DR: In this article, a quasi-ideal reverberation chamber (RC) minimum frequency is defined, which corresponds to the frequency where an RC is considered as working in a ''quasi ideal regime'' based on the assessment of the electromagnetic (EM) field distributions obtained in the working volume.
Abstract: An original method allowing to define a particular frequency called “quasi-ideal reverberation chamber (RC) minimum frequency” is presented. This frequency corresponds to the frequency where an RC is considered as working in a “quasi-ideal regime.” According to the definition of an ideal RC, the method is based on the assessment 1) of the electromagnetic (EM) field distributions obtained in the working volume (in comparison with the distributions obtained in the ideal model defined by Hill [D. A. Hill, “Plane wave integral representation for fields in reverberation chambers,” IEEE Trans. Electromagn. Compat., vol. 40, no. 3, pp. 209--217, Aug. 1998.]) and 2) of the number of uncorrelated samples obtained over one mode stirrer revolution. The method is considered as helpful in order to optimize the functioning of an RC at low frequencies for broadband EM compatibility immunity and emission tests. Indeed, it is shown from experimental and numerical results that the insertion of an optimal loading in the chamber allows to decrease the frequency where the chamber works quasi-ideally. The influence of complexifying the mode stirrer geometry is also discussed.
TL;DR: In this article, a novel active cancellation circuit for reducing common mode (CM) noise in vehicular three-phase ac motor drives is described, which features a feed-forward voltage-detecting-voltage-compensating structure.
Abstract: A novel active cancellation circuit for reducing common-mode (CM) noise in vehicular three-phase ac motor drives is described. The cancellation circuit features a feed-forward voltage-detecting-voltage-compensating structure. Unlike other voltage-compensating circuitry employing CM transformers on the thick phase wires, the proposed circuit is compactly integrated on the inverter printed circuit board. A prototype low-voltage space-vector-pulse-width-modulation (SVPWM) inverter employing this active cancellation technique was built and tested. This cost-effective and light-weight circuit significantly reduced the CM noise at the fundamental switching frequency and harmonics up to 2 MHz.
TL;DR: In this paper, the modified earth return impedance and Wise's earth-return admittance were used to evaluate wave propagation characteristics on a multiconductor in a high-frequency region, and the results showed that the aerial mode also shows Sommerfeld-Goubau propagation when the separation between conductors is large and the earth resistivity is high.
Abstract: Carson's, Pollaczek's, Wise's, and Sunde's earth-return impedances of an overhead line have been examined, and errors involved in the formulas are explained. Modified Pollaczek's and Carson's/Sunde's formulas are described. Wave propagation characteristics on a multiconductor in a high-frequency region are evaluated by adopting the modified earth-return impedance and Wise's earth-return admittance. Sommerfeld-Goubau propagation in a high-frequency region, which shows transition between transverse electromagnetic and transverse magnetic propagation, has been confirmed in the calculated results which agree with those predicted by Kikuchi for a single conductor. On a multiconductor system, it is found that the aerial mode also shows Sommerfeld-Goubau propagation when the separation between conductors is large and the earth resistivity is high.
TL;DR: In this article, the authors focused on the analysis of the shielding properties of reinforced concrete under impinging high-altitude electromagnetic pulse and found that reinforced concrete provides frequency-dependent shielding effectiveness mainly due to the embedded metallic grid rebars.
Abstract: This paper is focused on the analysis of the shielding properties of reinforced concrete under impinging high-altitude electromagnetic pulse. The reinforced concrete provides frequency-dependent shielding effectiveness mainly due to the embedded metallic grid rebars. For characterization of the concrete, three different configurations, i.e., concrete, rebar, and combined reinforced concrete, are analyzed in detail. In addition, the electromagnetic properties of concrete are quantitatively analyzed by its frequency dependence, moisture content, and material mixture ratio. According to the obtained results, as the rebar spacing decreases and the rebar diameter is increased, the transmission coefficient is gradually decreased. In particular, for reinforced concrete with built-in double layered rebar, it is possible to obtain a transmission coefficient approximately 40 dB less than that achieved by single rebar.
TL;DR: In this paper, the characteristics of radiation noise from an LED lamp and its effect on the bit error rate (BER) performance of an orthogonal frequency division multiplexing (OFDM) system for digital terrestrial television broadcasting (DTTB) were investigated.
Abstract: The characteristics of radiation noise from an LED lamp and its effect on the bit error rate (BER) performance of an orthogonal frequency-division multiplexing (OFDM) system for digital terrestrial television broadcasting (DTTB) are investigated. The waveform and frequency spectrum of radiation noise from an LED lamp are measured. A sequence of noise pulses is observed, caused by the switching circuit of the LED, and spread over the broadcast band of Japan. The relationship between the radiation noise from the LED lamp and its effect on the BER performance of the OFDM system using 64-quadrature amplitude modulation (64QAM) is evaluated using amplitude probability distribution (APD) measured with various resolution bandwidths. The behavior of the APD of the noise is similar to Gaussian noise when the resolution bandwidth becomes narrow. The BER performance of the OFDM system subjected to the noise of the LED lamp is estimated from the APD results, which agree well with measured results subjected to the LED noise. The characteristics of sequential LED noise are similar to the effect of Gaussian noise on the BER performance of the OFDM system for DTTB. Therefore, the APD measurement is a useful method to estimate the characteristics and effect of noise from an LED lamp on the OFDM system.
TL;DR: In this paper, the average measured channel attenuation exhibits values between 16.36 and 26.95 dB with a mean of 20.75 dB in the frequency band from 10 to 500 kHz.
Abstract: This paper presents a novel statistical characterization of the indoor low-voltage (LV) narrowband power line communication (PLC) channel in CENELEC and FCC/ARIB bands. Experimental measurements of electrical network complex transfer functions were used to determine, for the frequency range up to 500 kHz, the statistics of the average channel gain, the delay spread parameters, the coherence bandwidth and the channel capacity. The average measured channel attenuation exhibits values between 16.36 and 26.95 dB with a mean of 20.75 dB in the frequency band from 10 to 500 kHz. The root mean square (rms) delay spread has a mean value of 2.12 μs with 90% of the channels revealing values below 3.20 μs. The minimum coherence bandwidth at 0.9 correlation level is of 1.23 kHz and the mean channel capacity is of 5.32 Mbps. The lognormal behavior is confirmed and justified for the rms delay spread but not for the average channel gain. The negative correlation between these two parameters is examined, and the relationships between the different studied metrics are also explored.
TL;DR: In this article, a commonmode EMI active filter for dc-fed motor drives is proposed, which performs both the compensation of the CM voltage at the motor input and mitigation of the leakage high-frequency CM currents, thus increasing the drive reliability and the vehicle electromagnetic compatibility.
Abstract: A novel common-mode (CM) EMI active filter for dc-fed motor drives is proposed. The active filter performs both the compensation of the CM voltage at the motor input and the mitigation of the leakage high-frequency CM currents, thus increasing the drive reliability and the vehicle electromagnetic compatibility (EMC). The filter scheme is based on a voltage feedback action and also includes a feed-forward action by exploiting a suitably estimated CM current. An optimized design of the CM voltage detection/injection systems is implemented. Moreover, the active filter is supplied by a smaller voltage than the dc link value; this permits a more performing amplifier to be used. The active filter behavior is analyzed theoretically and its performance is assessed by experiments. The realized prototype shows a good efficiency and compactness.
TL;DR: In this paper, an effective layer model is proposed to predict the EM shielding performances of metallic wire grids typically used as protective layers in carbon fiber-reinforced composite laminates for aeronautical applications.
Abstract: An effective-layer model is proposed to predict the EM shielding performances of metallic wire grids typically used as protective layers in carbon fiber-reinforced composite laminates for aeronautical applications. The model is valid over a wide frequency range and it takes into account the field penetration through the grating. The shielding performance of the wire grid is estimated by means of the average shielding effectiveness, which represents the response of the material to an incident plane wave having both transverse-magnetic and transverse-electric polarizations. The proposed model is validated by comparison with experimental data, which demonstrates its validity over a wide frequency range, up to 18 GHz.
TL;DR: In this paper, the effect of ground stratification on underground fields generated by lightning discharges was analyzed for close distances (10 m-100 m from the channel) using the finite-difference time-domain technique.
Abstract: We present an analysis of the nearby electromagnetic fields generated by lightning discharges in the presence of a horizontally stratified, two-layer ground. To the best of our knowledge, this is the first time the effect of ground stratification on underground fields generated by lightning is analyzed. The analysis is performed by solving Maxwell's equations using the finite-difference time-domain technique. The return stroke channel is modeled using the modified transmission line model with exponential decay. The effect of the soil stratification on both above-ground fields and the fields penetrating into the ground is illustrated and discussed for two different cases characterized, respectively, by an upper layer more conductive than the lower level, and vice versa. The analysis was carried out for close distances (10 m-100 m from the channel). It is shown that, for these distances, the ground stratification does not significantly affect the electromagnetic fields above the ground. The above-ground vertical electric field and the azimuthal component of the magnetic field can be calculated assuming the ground as a perfectly conducting plane. The above-ground horizontal electric field is essentially determined by the characteristics of the conductive layer and it can be computed considering a homogeneous ground characterized by the conductive layer conductivity as long as the depth of the upper layer remains below 10 m or so. In general, the fields penetrating into the ground are markedly affected by the soil stratification. The electromagnetic field components inside the stratified soil are generally characterized by faster rise times compared to those of the field components in the case of a homogeneous ground with the upper layer characteristics. The peak value of the horizontal electric field is found to be very sensitive to the ground stratification. The horizontal electric field peak decreases considerably in the presence of a lower layer of higher conductivity. On the other hand, the presence of a lower layer with lower conductivity results in an increase of the peak value of the underground horizontal electric field.
TL;DR: In this article, a Monte Carlo method is used to take into account the random nature of lightning parameters and the influence of insulation level and spacing between surge arresters on lightning flashover rates is analyzed with the procedure.
Abstract: This paper presents a procedure for evaluation of lightning performance of overhead distribution lines. Because both voltages from direct strokes and nearby strokes may cause flashovers in distribution lines, flashover rates due to them need to be analyzed. The procedure is implemented in electromagnetic transient program, and the Monte Carlo method is used to take into account the random nature of lightning parameters. The lightning-induced voltages are calculated with an equivalent circuit derived from Agrawal formula. The influence of insulation level and spacing between surge arresters on lightning flashover rates is analyzed with the procedure. For a line with low-insulation level about 150 kV above high conductivity ground or with high-insulation level about 300 kV above low conductivity ground, the spacing between arresters is best less than 400 m. But for a line with low-insulation level above low conductivity ground, it is better to reduce the spacing to 200 m.
TL;DR: A proficiency test through interlaboratory comparison of radiated emission measurements was carried out in the period of time comprised between May 2012 and May 2013 as mentioned in this paper, where 19 test houses took part in the exercise providing 91 measurement results in total.
Abstract: A proficiency test through interlaboratory comparison of radiated emission measurements was carried out in the period of time comprised between May 2012 and May 2013. Nineteen test houses took part in the exercise providing 91 measurement results in total. Measurements were performed in anechoic chambers and in the frequency range comprised between 200 and 3000 MHz. A traveling sample circulated among the laboratories, generating a reference electromagnetic field whose amplitude was a priori known (with uncertainty) but not revealed to the participants until the end of the comparison. Measurement results were provided by the participants in terms of best estimate and uncertainty. The aggregate measurement result is here compared with the a priori known value and its uncertainty. The performance of the laboratories, quantified in terms of two performance statistics selected from ISO 13528, is analyzed and discussed. The measurement uncertainty declared by the laboratories is compared with the dispersion of the measurement results. Aspects concerning the design and conduct of the comparison are also presented and discussed.