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A low profile dual-band frequency selective surface (FSS) for shielding the GSM applications is presented in this paper. The proposed FSS contains the unit cell made of modified double square loop elements with paper as its substrate. The overall thickness of the proposed FSS measures only 0.55 mm. The FSS offers band stop response at 930 and 1720 MHz with 18 dB shielding effectiveness for a bandwidth of 100 and 173 MHz, respectively, thus shielding the GSM signals. Additionally, the modified double square loop element-based FSS is symmetrical providing the advantage of polarization independency. It also exhibits angular stability up to 60° for both the horizontal polarized electric field (TE mode) and vertically polarized electric field (TM mode). A prototype of the proposed dual-band low profile FSS is fabricated. The simulation results are compared with the experimental results and are found to be in congruence with each other. [ABSTRACT FROM PUBLISHER]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

The mechanism of the passive intermodulation (PIM) distortion caused by the loose contact in coaxial connectors is of great importance in wireless communication systems. This paper focuses on the effect of the additional impedance on PIM levels in coaxial connectors. First, the additional impedance and PIM levels of the loose contact coaxial connectors are measured. Then, the S-parameters and the additional impedance with three different loose contact cases are simulated. Finally, a modified coaxial connector with different values of conductive tapes is designed to verify the additional impedance impacts on the PIM level. It is shown that the increase of the additional impedance of the metal–metal loose contact will lead to the deterioration of PIM levels in the coaxial connector. [ABSTRACT FROM AUTHOR]

The work presented in this two-part paper focuses on a prediction method of the radiated susceptibility of integrated circuit and printed circuit board from near-field scan injection, in order to anticipate risks of noncompliance due to design weakness. In Part I, a worst-case estimator of the far-field induced voltage on a PCB trace was proposed. Based on it, an estimator of the radiated susceptibility of a printed circuit board based on near-field scan results is derived and validated through two validation case studies. [ABSTRACT FROM AUTHOR]

This article presents the design and analysis of a flexible wideband absorber comprising a resistive ring-shaped frequency-selective surface (FSS). In this article, a novel conductive material is used for the designing and fabrication of the absorber. The structure consists of two different-size rings arranged diagonally as an FSS and printed on a flexible photo paper substrate material using screen printing technology and backed with a copper ground plane. The unit cell dimension is 0.64 $\,\lambda _{l}$ × 0.64 $\,\lambda _{l}$ × 0.088 $\,\lambda _{l}$ , where $\lambda _{l}$ is the wavelength at the lowest absorption frequency. The fractional bandwidth of the proposed absorber is 86.2%, which covers $X$ and Ku bands completely and the lower portion of the $K$ -band. The proposed absorber shows more than 90% absorption in the frequency range of 8–20.12 GHz at different angles of polarization. The effect of various design parameters of the FSS, such as period of unit cell, thickness of the substrate, interelement spacing, and width of the rings, is examined and verified based on the simulation, circuital, and experimental model. [ABSTRACT FROM AUTHOR]

Electrostatic discharge (ESD)-induced soft failures are a critical issue for electronic systems as the failures are mostly found after the hardware design is completed. Any changes applied to the hardware may delay the project. Diagnostic tools capable of identifying soft failure-induced malfunctions in an early stage of product design help to reduce the risk of late stage ESD-induced project delays. In many cases, soft failures can be directly observed by the user interface, system crash, or other obvious indicators. However, in an early product design stage the operation system may be marginal and applications may not be available. To improve the ability to detect soft failure critical design choices, this paper presents several methods to identify ESD-induced changes which may not be observable via direct observation. These methods include the observation of ac or dc currents, monitoring dc voltages, capturing near fields and processing them via short-term fast fourier transform (FFT), wavelet transformation, down mixing to audible range, and monitoring for latch-up via thermal imaging. The paper introduces the basis of each method, shows examples, and compares them for their detection ability. [ABSTRACT FROM AUTHOR]

This paper presents the study of the fitting method for the sensitivity calibration data of a time-domain high-altitude electromagnetic pulse (HEMP) measuring system combined with the engineering practice. Due to the simple and practical requirements in engineering applications, this paper discussed and compared three different fitting methods and two different fitting models typically used in the HEMP measuring system: conversion coefficient averaging method, least square method, and relative least square method with direct proportion model and linear model. Uncertainty is used as the judgment of fitting performance in this paper. Both type A and type B uncertainties are analyzed. The statistical method is used in the analysis of type A uncertainty. Results of 50 different measuring systems with a different fitting method are observed and compared. And the standard deviation is used to represent the relative standard uncertainty of fitting. The GUM method with an ideal linear assumption of the sensitivity is used and the strict expressions of uncertainties are deduced in the analysis of type B uncertainty. The results show that the relative least square method is more suitable than the least square method in the fitting of HEMP measuring system calibration. The averaging method with direct proportion model is preferable considering the convenience and efficiency in practice. And the relative least square method with both the direct proportion model and linear model can be considered as well. The least square method with the linear model is not recommended in the application of time-domain HEMP measuring systems. [ABSTRACT FROM AUTHOR]

This paper introduces a generalized approach of the linear combination of configuration field (LCCF) method. The technique developed in this paper provides a way to identify the temporal profile of electromagnetic sources satisfying particular properties for a given target (fields, voltage, or current). Here, we focus on identifying voltage signals that would lead to a specified voltage over a time interval at some points of a network. To experimentally apply the same idea, we propose two possibilities to decrease the maximum frequencies of the voltage signals. The LCCF method is then applied to bring a software correction to a lossy transmission-line network presenting soft or hard defects. [ABSTRACT FROM AUTHOR]

For extended critical infrastructures such as the power grid, electromagnetic compatibility (EMC) testing of electronic components alone is not sufficient to assess the risk of electromagnetic (EM) attacks. This paper presents results on a methodology for high-power EM based risk assessment of large structures considering the example of smart grid substations. The evaluation involves control, protection, and communication equipment used in substations as part of supervisory control and data acquisition systems and ready for the smart grid. The methodology developed in this paper evaluates the threat, vulnerability, impact, and protective measures as indicators in various scenarios of both conducted and radiated intentional EM interference (IEMI) threats to these systems. In order to assess these indicators, fundamental data on available IEMI sources, generic substation layouts, and their mitigating effects, coupling paths, and IEMI susceptibilities has been gathered in several test campaigns and studies. Electrical field strengths generable by commercially available power sources inside substations have been estimated considering measured shielding characteristics of the buildings and attainable target distances. A comparison with measured susceptibilities of control equipment to IEMI reveals noticeable security issues. In particular, expected field strengths inside substation buildings can be much higher than the immunity levels for control systems as requested in EMC standards. [ABSTRACT FROM AUTHOR]

The nonlinear autoregressive network with exogenous inputs (NARX) is a recurrent dynamic neural architecture, which is commonly used for input–output modeling of nonlinear dynamical systems. Due to the lack of accurate mathematical model for the performance analysis on surge protective devices (SPDs), with the input of fast rising time electromagnetic pulse (FREMP), the NARX neural network is employed to predict the response characteristics of SPD in this paper. In order to verify the feasibility of this method, SPD test system is set up according to IEC 61000-4-24. The results show that the response curve estimated by the proposed model is in good agreement with experimental results, especially the waveform parameters such as response time, pulse peak, and residual voltage. The good forecasting performance of the network suggests that the NARX model used in this paper has good generalization ability. Moreover, with less measured data it can predict the response of the SPD under different voltage levels that were not yet measured. [ABSTRACT FROM AUTHOR]

This paper proposes a generator polynomial model-based eye diagram estimation method for the error-correction codes (ECCs), which are the Bose–Chaudhuri–Hocquenghem (BCH) code and the Reed–Solomon (RS) code. The ECCs compensate for the channel loss at the bit level, so most of the systems include the ECC block. The BCH and RS codes are the generator polynomial-based ECCs; this paper proposes the generator polynomial model-based method. The model provides the accurate probability density function of the code words for the BCH and RS code. Thus, the proposed method is capable of achieving the signal integrity analysis for the system level. For verification, we design the BCH and RS encoders. The estimated eye diagrams are nearly the same as that of the transient simulation for the BCH and RS codes. Furthermore, the voltage bathtub curves are the same up to 10−8. For a smaller bit-error rate value, the proposed method only provides the bathtub curve. This paper successfully verifies the eye diagram estimation method for the BCH and RS codes. [ABSTRACT FROM AUTHOR]

This paper proposes eye diagram estimation methods for linear feedback shift register (LFSR)-based bit streams in pseudorandom binary sequence (PRBS) test and scrambling. The PRBS test uses the LFSR as a random data source; scrambling suppresses the radiated EMI by exclusive-OR (XOR) between the data and the LFSR. Both cases include the LFSR as the last block, thus, the LFSR dominantly determines the eye diagram. This paper introduced the deterministic and statistical eye diagram for the PRBS test and scrambling, respectively. The deterministic eye diagram was verified by comparing to the measurement; the statistical eye diagram was verified by comparing to the transient simulation. We also compared the voltage bathtub curves for the scrambling. The measurement and proposed method were correlated up to the BER of 10−10. [ABSTRACT FROM AUTHOR]

The fifth generation (5G) of mobile communications givesbirth to the evolution of the base stations. They progressively include arrays of antennas in the sub-6 GHz frequency band worldwide. Moreover, 5G takes advantage of the beamforming capabilities to gain power efficiency and higher throughputs. Within this framework, achieving high decoupling performance between any pairs of antennas and compactness at the same time become a major challenge. The present paper describes an advanced solution based on the interposition of a thin and low-profile absorbing wall operating in the 3.4–3.6 GHz frequency band. The absorption is provided by a frequency selective surface whose elementary pattern size is first optimized. Then, the compact absorbing wall that associates back-to-back pieces of absorber is interposed between elements of an antenna array. Moreover, the fabrication of both antenna array and decoupling device involve lightweight and low-cost composite technology. The results show that such a compact decoupling device achieves excellent decoupling capabilities while keeping up the antenna array performance. [ABSTRACT FROM AUTHOR]

A cost-effective, conformal, polarization-insensitive, light-weight, ultrathin, and ultrawideband electromagnetic wave absorber covering the entire Ku, K, and Ka bands and the lower V band is presented in this article. The absorber consists of a single layer of inkjet printed resistive metasurface laid over a flexible paper supported by a grounded foam. A novel metasurface pattern is designed by combining a checkerboard inspired symmetrical structure around a central square patch. The notable features of the proposed absorber are its ultrathin thickness of 2.17 mm (0.09 $\boldsymbol{\lambda _l}$ at the lowest operating frequency) for achieving a fractional bandwidth of 117% with a small radar cross section and its suitability for conformal applications. It exhibits more than 90% absorptivity over a frequency range from 11.87 to 45.28 GHz for all the angles of polarization and is also angularly stable. The theoretical, simulation, circuital, and experimental analysis validates the various features exhibited by the absorber. [ABSTRACT FROM AUTHOR]

The objective of this article is to devise a cost-effective, conformal, polarization-insensitive, and broadband metamaterial absorber for X-band applications. A periodic subwavelength conducting grid pattern is printed over flexible papers in a multi-layered fashion to achieve the broadband behavior. A silver nanoparticle incorporated inkjet printing technique is employed that does not require any post-processing such as sintering. The absorber is eco-friendly and suitable for rapid mass production at a low-cost. Moreover, the printed patterns do not crack when bent or applied over curved surfaces. The characteristics, working principle, and equivalent circuit of the absorber are described. The absorber is designed on a 1.06 mm (0.03 λl at the lowest working frequency) ultrathin substrate. It exhibits more than 90% absorptivity from 8.43 to 10.38 GHz for all angles of polarization with wide angular stability up to 45°. The flexibility and broadband feature is also confirmed by the experimental measurement of the fabricated prototype. [ABSTRACT FROM AUTHOR]

Dependence of lightning electric field waveform parameters on distance between the lightning channel and the field measuring point is examined. The analyses are performed based on representative wideband electric field waveforms that were obtained by averaging individual waveforms produced by negative return strokes at distances ranging from 10 to 500 km. The methodology employed for finding the representative waveforms using a large database is described in the companion paper. In this article, we present evolution with distance of the following waveform parameters: zero-to-peak rise time, zero-crossing time, ratio of the initial electric field peak to the opposite polarity overshoot, all for the ground wave, and the ratio of the ground wave initial electric field peak to the peak of the first skywave. We also present a catalog of representative waveforms for different distances, time of day, and stroke order. Additionally, we examine the peak-to-peak and zero-to-zero time intervals between the ground wave and the first skywave that are often used for estimating the apparent ionospheric reflection height. [ABSTRACT FROM AUTHOR]

A new approach to the characterization of CG lightning electric field waveforms using a large database is presented. The waveforms, recorded in a wide (160 Hz–500 kHz) frequency range, are categorized into groups, depending on stroke order (first or subsequent), time of day (to distinguish between the daytime and nighttime ionosphere heights), and distance range. For each group, a representative waveform (including the ground wave and one-hop skywave) was found by averaging a large number of individual amplitude-normalized waveforms on a -100 to 500 μs time scale (t = 0 corresponds to the peak of the return-stroke ground wave). In this article, the methodology of waveform classification and averaging is presented and discussed. In the companion paper, the developed methodology is applied to analyzing variation of lightning electric field waveforms of different type with distance in the 10 to 500 km range. [ABSTRACT FROM AUTHOR]

Crosstalk noise on the printed circuit board is usually decreased by adding shielding ground (GND). In the trace routing area, the shielding vias are added to isolate the coupling between different traces. In the ball gate array (BGA) and pin field area, assigning more GND pins has demonstrated the effectiveness of crosstalk reduction between signals. However, such design decreases the signal to ground (S:G) ratio dramatically, herein, it is not suitable for applications that require high signal pin density. Unlike the treatment in the conventional methodology, in this paper, the differential crosstalk is mitigated by using the principle of symmetry on two adjacent differential signal pairs in the BGA and pin field regions. New full pin map patterns are proposed and compared with the conventional full pin map patterns. Without sacrificing the S:G ratio, the proposed maps prove the superiority in mitigating both differential far-end and near-end integrated crosstalk noise. To maintain the low crosstalk level in the entire link path, guidance of differential trace routing is provided and demonstrated in the details. All models in this paper satisfy SerDes channel designing and manufacturing requirements. [ABSTRACT FROM AUTHOR]

In this paper, mitigation of unwanted radiated electromagnetic emissions from a high-speed system enclosure using metamaterial-based absorbers is investigated. First, the performance of an earlier introduced frequency selective metamaterial absorber is thoroughly evaluated via full-wave simulations and compared with that of a commercial thin microwave absorber. An experimental in-lab test set-up is developed to validate simulation results confirming that a stronger mitigation of radiated emissions is delivered by the proposed absorber. The measured radiated emission patterns closely follow simulated results and confirm better than 5 dB reduction in emissions when the proposed absorber is included in the enclosure box. Simulations with simultaneous excitation of multiple radiation sources inside the box prove the effectiveness of the developed absorber in realistic operational conditions that could include array effects for unintentional radiation sources. A second absorber design is introduced in this paper with improved thermal conductivity while providing emission reduction better than 4.6 dB. [ABSTRACT FROM AUTHOR]

This paper presents a novel method for optimizing a planar elliptical dipole antenna with elliptical slots, for ultrawideband electromagnetic compatibility applications. The antenna is required to achieve minimum return loss and boresight realized gain with an adequate gain flatness across the frequency range of 1–5 GHz. Such an antenna is a powerful tool for electromagnetic measurements, due to its very compact size and its wide operating bandwidth. The main optimization method used in this paper is the invasive weed optimization (IWO), which is a nature-inspired metaheuristic evolutionary algorithm. The conventional and a modified version of IWO are compared to other prior-art evolutionary algorithms, such as the particle swarm optimization and differential evolution. The comparison is performed by applying all the methods on a set of mathematical test functions and also on the specific antenna design problem presented in this paper. The comparative results demonstrate the superiority of the modified IWO over the other optimization methods. [ABSTRACT FROM AUTHOR]

This paper presents a statistical-test-based methodology for evaluating the electromagnetic (EM) emanations from mobile touchscreen devices. These EM emanations potentially contain information that can be exploited to reconstruct screen images of the device remotely. The proposed method evaluates the threat of such EM-based information leakage by performing a statistical test of measured EM waves and environmental noise without performing ad-hoc screen restoration or image processing. In particular, we employ the Kolmogorov–Smirnov test, a nonparametric statistical test method, to compare two distributions of radiated EM waves: one that potentially contains screen information and another with environmental noise. In addition, this paper demonstrates the validity of our methodology via experiments involving authentic tablet devices in real-world settings and discusses a possible method to determine the confidence interval that can be adopted as a criterion for security evaluation depending on the environment. [ABSTRACT FROM AUTHOR]

High-speed digital signals may generate significant radiated emission and affect nearby wireless communication devices. The undesirable electromagnetic interference (EMI) of USB 3.0 to the 2.4-GHz ISM band is a well-known example. Common solutions such as shielding or layout improvement usually focus on controlling the coupling path, while few works considered the possibility of using data encoding. Based on our previous work, this paper presents a new coding method to reduce EMI at the source, with a key feature of being compatible with the conventional 8b/10b line code. In particular, the control symbols in 8b/10b are used to achieve spectrum suppression at specific target frequencies. By properly inserting preselected control symbols constantly to the output stream, a single band 7–15 dB, or dual band near 10 dB, spectrum reduction can be achieved, hence opening a window in spectrum suitable for wireless communication. The proposed coding demands a new encoder at the transmitter side, but only a slightly modified 8b/10b decoder is required at the receiver side. Various simulation and measurement validations are presented in this paper, and a real-time encoder implemented on a field programmable gate array is demonstrated. [ABSTRACT FROM AUTHOR]

Every electronic device that processes information becomes a source of spurious emissions. These emissions can be used in the process of electromagnetic eavesdropping, resulting in the possibility of obtaining information in a non-invasive manner. The graphic tracks of information systems are particularly sensitive sources of such emissions. This paper analyzes the levels of electromagnetic interference from two graphic standards: video grafics array (VGA) and digital video interface (DVI). The DVI standard, due to the assumptions made by the Digital Display Working Group, was to replace the analog VGA standard and increase the electromagnetic safety of transmitted graphic data. However, the reality and ongoing research did not confirm this. The DVI digital standard, as a source of spurious emissions, must be protected in the same way as the VGA standard. This paper analyzes the impact of the color method on levels of electromagnetic interference for the two considered graphic standards. The color method (the right color for the background and text) is one of the solutions that can counteract the process of electromagnetic eavesdropping. The proper selection of colors can limit the level of electromagnetic interference but only in the case of the VGA standard (change in the amplitude of the voltage of the electrical signal). The DVI standard, due to a different way of color coding (the value of voltage amplitude of the electrical signal is constant; the shape of the signal changes), does not show any relation between the choice of background colors and text or the level of generated electromagnetic interference. Very often, this interference has the characteristics of information being processed and becomes valuable in the process of electromagnetic infiltration. That is why, the analog VGA standard is still widely used in information systems, where the most important aspect is the protection of information against electromagnetic penetration. [ABSTRACT FROM AUTHOR]

This paper presents a method to determine the frequency where a reverberation chamber starts to be “well stirred” according to the number of stirring conditions (i.e., different positions of a mode stirrer for a mechanically stirred chamber) considered. The method, based on $S_{11}$ measurements of an antenna inserted in the reverberation chamber to be characterized, requires a simple measurement setup, is fast (few minutes) while leading to an excellent level of accuracy (maximum uncertainty of 10%) as demonstrated by the measurement results shown in this paper. The method takes advantage of a reliable definition of the well stirred condition leading to threshold values theoretically justified. Clear measurement guidelines and recommendations on the post-treatment process (available on demand) are also given. The method, proposed to the community of users as an alternative calibration procedure, provides reliable information on the chamber performances in the “grey zone” between the lowest usable frequency defined by standards and the frequency when the chamber is actually well stirred. [ABSTRACT FROM AUTHOR]

Impulse Radiating Antenna (IRA) is a highly efficient antenna that has a number of applications in both civilian and military sectors. These antennae produce fast rising pulses in a narrow beam that can give rise to high intensity electromagnetic fields having a wide impact on electrical and electronic systems. One such area where the impact becomes prominent is the present day telecommunication network. This system consists of buried coaxial cables connected to sensitive equipments at their terminations. Henceforth, there could be situations where the incident IRA field can interfere with the cables laid in the area. As the cables pass over different regions with varied soil texture and characteristics, the proportion of the IRA field incident on it will vary, that is dependent upon the nature of the soil in which the cable is buried. This paper reports the response of different types of soils to incident IRA fields and the induced voltage in a cable buried in such soils. A case study of different types of soils is also included in the paper. It is found that the soils in industrial areas are more prone to electromagnetic interference from IRA rather than in a highly moist ground. [ABSTRACT FROM AUTHOR]

The Cooray–Rubinstein formula (C–R formula) has been widely used to calculate the horizontal electric field generated by a lightning return stroke over the lossy ground. To evaluate the time-domain C–R formula by a recursive convolution, an alternative method is proposed in this paper, where the formulation in terms of the “step response” corresponding to the ground surface impedance, denoted as $k_{\varepsilon }(t)$ , is evaluated by the numerical inverse Laplace transform (NILT). Considering the good performance of Talbot's method for the NILT, Talbot's method is adopted to express $k_{\varepsilon }(t)$ in terms of a series of exponential functions, which can avoid the tedious piecewise approximation used by the available method and make the recursive convolution easier to program. In addition, some key formulae for the recursive convolution with complex poles and residues are presented in this paper. Numerical examples are provided to validate the proposed method. [ABSTRACT FROM AUTHOR]

This paper analyses the inherent difficulties in measuring the horizontal electric field from lightning and proposes some solutions to mitigate the contamination effect of the overwhelming vertical electric field. The analysis is carried out with a set of time-domain equations for the calculation of the electromagnetic fields from lightning. As these equations are scattered in several publications, in this paper they are compiled and presented in a harmonized form. Moreover, one new expression for the vertical electric field slightly below the ground surface is presented. It is shown that the horizontal electric field at the surface of lossy ground can be measured with minimum disturbance caused by the vertical electric field if the field sensor is placed slightly below the ground surface. This paper also shows that the horizontal electric field above the ground surface could be measured with the help of a pair of field sensors conveniently arranged so that the influence of the vertical electric field on the measurement is cancelled. [ABSTRACT FROM AUTHOR]

Modeling of lightning return-stroke channel affects significantly the estimation of fast-front overvoltages arising across overhead line insulators, thus, also the lightning performance of power lines. This paper introduces a simplified method for estimating the minimum lightning currents causing shielding failure flashover and backflashover of overhead transmission line insulation, as affected by lightning channel equivalent impedance. The validity of the proposed methodology is demonstrated through ATP-EMTP simulations of typical 66 up to 765-kV overhead transmission lines with variable tower ground resistance. An assessment is made of the effects of lightning channel equivalent impedance on the lightning performance of overhead lines, that is, shielding failure flashover and backflashover rates. Lightning channel equivalent impedance values of 1000 and 400 Ω are suggested, respectively, for shielding failure and backflashover studies, based on the results obtained in this paper together with a discussion on the literature data regarding channel impedance. [ABSTRACT FROM AUTHOR]

The frequency dependence as well as the current dependence of grounding resistance affects lightning overvoltages in electric power system. This paper proposes an equivalent circuit to simulate the frequency dependence of soil resistivity and permittivity. Constants of the equivalent circuit are determined based on empirical formulas for the frequency dependence of the soil parameters proposed by Alipio and Visacro. The equivalent circuit is represented in time domain. Therefore, the equivalent circuit is applicable to the calculation of the current dependence of the grounding resistance. An influence of the frequency dependence of the soil resistivity and permittivity on the current dependence of the grounding resistance is discussed by the use of the equivalent circuit. This paper proposes a modified CIGRE model to calculate the current dependence of the grounding resistance. The equivalent circuit is very convenient and useful for engineers to carry out lightning surge analysis. [ABSTRACT FROM AUTHOR]

This paper analyzes three time-domain expressions for the surface impedance, which allows the calculation of the horizontal electric field produced by a lightning return stroke. They are the expression obtained by Barbosa and Paulino directly in the time domain, the expression obtained by Andreotti et al. as a time-domain counterpart of the Cooray–Rubinstein formula, and an approximate expression derived independently from the two former expressions. The analysis is carried out by comparing the kernels of the expressions and by comparing the lightning-induced voltages (LIVs) on an aerial line. The results show that the two former expressions provide almost identical LIVs, while the approximate one provides peak values from 5% to 7% lower than those provided by the other expressions. A detailed discussion of the results is included in the paper. [ABSTRACT FROM AUTHOR]

In this paper, we study the effect of overhead shielding wires on the lightning-induced voltages of two typical multiconductor lines configurations at distances from 50 to 1000 m from the lightning channel, considering perfect and lossy ground, respectively, by using the 2-D finite-difference time-domain method and Agrawal field-line coupling model. The results show that the effect of overhead shielding wires on the lightning-induced voltages is closely related to the finite ground conductivity (σ) and the observation distance (d) from the lightning channel. For the ground conductivity ranging from 0.1 to 0.001 S/m, the values of shielding factor (SF) range about from 0.7 to 0.8 for vertical configuration, and range about from 0.6 to 0.7 for horizontal configuration, within distances from 50 to 1000 m from the lightning channel. Also, we have compared the SF values predicted by using Rusck simplified formula with ours in this paper, and it is noted that the Rusck simplified formula underestimates the SF values and the errors may be above 10% under poor ground conductivities of 0.001 S/m when distances larger than 500 m. [ABSTRACT FROM AUTHOR]

We provide, in detail, three examples of the application of our stochastic model (a companion paper in this journal) that provides analytical expressions for the probability distribution of the propagation delay time of logic signals through a CMOS inverter when the inverter power supply voltage ${V_{{{\text{dd}}}}}$ (more precisely, gate voltage ${V_{\text{GS}}}$) is itself probabilistic for some reason (e.g., system noise or a random external electromagnetic disturbance). Since the propagation delay time is a function of the value of ${V_{\text{dd}}}$ , then some values of ${V_{\text{dd}}}$ may produce values of inverter propagation delay time that cause the circuit in which the inverter resides to malfunction (e.g., by resulting in a delay time value not conforming with the delay time margins for that circuit). The examples we present for some possible probability density functions (pdfs) for ${V_{\text{dd}}}$ are 1) Gaussian density, 2) uniform density on a finite interval, and 3) delta density. The Gaussian density is an example of a continuous one, whereas the uniform density is an example of a discontinuous one; the delta density is of interest for providing guidance in handling discrete pdfs—not explicitly treated in the above referenced paper—since such pdfs may be represented as weighted sums ofδ-functions. Based upon the derived inverter propagation delay time probability distribution, we derive, for the Gaussian density, a probability for the malfunction of a circuit containing a single inverter subject to such a stochastic ${V_{\text{dd}}}$. [ABSTRACT FROM AUTHOR]

We derive analytically expressions for the probability distribution of the propagation delay time of logic signals through a CMOS inverter when the inverter power supply voltage $V_{{\text{dd}}}$ (more precisely, gate voltage $V_{{\text{GS}}}$) is itself probabilistic for some reason (e.g., system noise or a random external electromagnetic disturbance). Since the propagation delay time is a function of the value of $V_{{\text{dd}}}$ , then some values of $V_{{\text{dd}}}$ may produce values of the inverter propagation delay time that cause the circuit in which the inverter resides to malfunction (e.g., by resulting in an inverter delay time value not conforming with the delay time margins for that circuit). Based upon the derived inverter propagation delay time probability distribution, we then derive a probability for the malfunction of a circuit containing a single inverter subject to such a stochastic $V_{{\text{dd}}}$. In this paper, we present no discussion of the application of our formalism to example probability density functions for $V_{{\text{dd}}}$ ; we rectify this situation by presenting three detailed such examples in a companion paper in this journal. [ABSTRACT FROM AUTHOR]

In this paper, a method is proposed to calibrate a probe by placing it into a known field and referencing its output voltage to the known field. A transmission line is a convenient structure for creating such a known field. This paper presents the effect of the inhomogeneous medium on the near-field generated over a grounded coplanar waveguide (GCPW) printed circuit board (PCB) and reports the field pattern over the GCPW. GCPW PCBs are used to determine the probe factor for near-field scanning applications. A near-field scan is performed to visualize the near-field sources over a device under test (DUT). The near-field is measured by using E- and H-field electromagnetic interference probes. The output of these probes is a voltage and using the probe factor, the field present over the DUT can be determined. To calculate the probe factor, the near-field strength needs to be known using the 3-D simulation. GCPW creates a quasi-TEM field. The effect of non-TEM modes is easily underestimated, such that non-TEM fields prevent the user from determining the unwanted field suppression of probes at higher frequencies. [ABSTRACT FROM AUTHOR]

This paper explores the characteristics of unidirectional carbon-fiber-reinforced-polymer (CFRP) laminas and their use in electromagnetic absorber design. Unidirectional CFRP composites have been used for decades in structural applications. The electromagnetic properties of unidirectional CFRP composites have been well documented in the open literature. Since many structural applications may also have specific electromagnetic compatibility requirements, it is logical to exploit the useful electromagnetic properties of unidirectional CFRP. Specifically, this paper investigates circuit-analog absorbers (CAAs) made from a unidirectional CFRP lamina, foam spacer, and a ground plane. The unique properties of the unidirectional CFRP sheet provide the necessary resistive and reactive properties for the development of a CAA. To investigate such a CAA, the electromagnetic properties of several off-the-shelf unidirectional CFRP laminas were measured from 4 to 18 GHz using a free-space measurement system. A surface-impedance representation of the unidirectional CFRP lamina was used to build rigorous transmission-line models that provide insights about the properties of the absorbing structure. Transmission line as well as full-wave models were compared to measured absorption performance of fabricated prototypes. Maximum absorption configurations were found to be highly dependent on incident polarization relative to fiber orientation. [ABSTRACT FROM AUTHOR]

An important aspect of ensuring the power integrity of a power distribution network (PDN) design is to determine the layout, value, package size, and number of decoupling capacitors. To solve the limitation of the vertical connection of the surface-mounting-type capacitor to the power net area fill, a new concept of a capacitor denoted the Z-directed component (ZDC) is proposed in this paper. There are many applications possible with the ZDC with the first implementation as a decoupling capacitor. The ZDC capacitors can be integrated within the printed circuit board (PCB) substrate directly below the package ball and eliminate the integrated circuit (IC) to decoupling capacitor horizontal distance across the power net area fill. Furthermore, the inductance associated with the vertical current paths on the vias from the IC package to the horizontal power net area fill and similarly for the surface-mounted technology decoupling capacitors is eliminated. Since only the inductance of the ZDC capacitor itself remains, there is the possibility of using far fewer capacitors to achieve a high-frequency target impedance specification. The ZDC is a promising technology that gives the PCB designer the opportunity to integrate low equivalent series inductance decoupling capacitors much closer to the noise source than traditional surface-mount capacitors. In addition, in this paper, a high-order model is introduced for the ZDC capacitor to better understand the high-frequency characteristics of the component and is verified with measurements. [ABSTRACT FROM AUTHOR]

This paper studies the optimized setup in the design-of-experiment (DoE) method to efficiently construct precise artificial neural network (ANN) model for high-speed channel. The accuracy of an ANN model is in general determined by the number of the training sets used in constructing the model. The more the training sets, the better the accuracy is. However, a large number of training sets can significantly increase the effort in obtaining these data (by time-consuming full-wave simulations in the case of channel analysis). Therefore, improving the accuracy while maintaining the same number of training sets by optimizing how the training sets are obtained is critical to develop an efficient ANN construction method. In this paper, different setups in a DoE method, which is used for training data set generation, are studied. Based on error analysis, an optimized setup is proposed. Finally, the performance of the proposed method is validated by the S-parameter simulations with arbitrarily-selected channel parameters within the ranges of interest. [ABSTRACT FROM AUTHOR]

This paper deals with magnetic field mitigation techniques for underground power systems by using conductive or ferromagnetic shielding plates. Two new aspects are considered in this paper beside the shielding effectiveness analysis: the contribution to the series impedance and power losses due to the conducting set formed by the shielding plate/earth return path. A finite thickness ferromagnetic or conductive shielding is assumed buried parallel to the soil/air plane surface in order to model the induction magnetic field mitigation of a power underground cable system in flat configuration. An analytical method, appropriate to deal with possible optimization procedures, is used based on the magnetic vector potential for multilayered configurations where the shielding plate is treated as a different layer. Results for the magnetic field reduction factor at the soil surface are obtained for different shielding materials, different shielding thickness values, as well as different frequency values. Results are validated by employing the finite element analysis. [ABSTRACT FROM AUTHOR]

The  power distribution network (PDN) of a high-speed printed circuit board requires a high-performance power supply. The total equivalent inductance above the top ground plane is an important part of PDN design and is regarded as Labove. In this paper, an inductance library for different structures of capacitor connections and capacitor sizes has been built, which is essential for PDN design. computer simulation technology (CST) and partial element equivalent circuit method are applied to obtain the shorted pattern design curves at various design data. The shorted pattern design curve means the total equivalent inductance varies with the distance between pad and ground plane. In addition, an approximate shorted model is established for a decoupling capacitor-mounted model, which will be convenient for us to get the inductance of Labove. In this paper, the design curve provides an intuitive guideline in designing PDN and facilitates the industry to choose what they want with consideration of the inductance, space, via numbers, etc. [ABSTRACT FROM AUTHOR]

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This article provides the implementation procedure, the validation, and some considerations on the computational efforts of the analytical expressions developed for the lightning electromagnetic fields presented in the companion paper. The validation is presented with different configurations in terms of channel-base current, ground conductivity, and distance to the lightning channel, comparing the obtained results with the numerical integration of the classical formulas. The comparative analysis shows a perfect agreement between the proposed analytical approach and reference numerical simulations. Moreover, the computational effort of the proposed method is discussed, focusing the attention on the choice of the points in which the channel has to be divided in order to maximize the CPU time savings without losing accuracy. [ABSTRACT FROM AUTHOR]

Emerging additive manufacturing methods facilitate the creation of enclosures with tailor-made shielding and scattering performance by using multiple conductive and dielectric layers. For a first analysis an elongated housing, with a cross-section small compared to the wavelength of the impinging electromagnetic field is replaced by an infinitely long multilayered cylinder. In a previous paper, we concluded that existing solutions of the Maxwell equations for this configuration are not accurate in calculating scattering. This also negatively impacts results for multilayer shielding. This article proposes a fast, time-harmonic formulation based on a combination of Bessel and Hankel functions as solution to the Helmholtz equation. Both electric and magnetic fields are considered and solutions are obtained independently for transversal and longitudinal source fields. These can be superpositioned to describe arbitrary source fields. The system of equations defined by the boundary conditions of the multilayer problem is solved via Gaussian elimination which can easily be automated with standard MATLAB or Octave functions. Results are compared to known approaches and applied to a dual-layer use case. The latter shows that shielding and scattering performance improves significantly with multiple layers compared to a single layer with equivalent thickness both for transversal and longitudinal fields. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper presents a practical approach toward efficient shielding of adjustable speed drives (ASD). The electromagnetic interference problem affects a complex roller rig testing facility that is developed at the Railway Technologies Laboratory of Virginia Tech. The rig uses a slew of sensitive instruments to study the wheel-rail contact mechanics in the railway applications. Eight ASDs run the rig in close vicinity of the sensors, which heavily affects their measurements. System requirements such as heat management, structural rigidity, size, and cost, restrict additional shielding for these drives. In this paper, a two-dimensional finite element analysis is used to find the proper shielding material, optimum thickness, and aperture size that maximize the shielding effectiveness. Based on the simulation results, an enclosure is fabricated for the VT Roller Rig control tower. Simulation results show that steel exhibits the least sensitivity to perforation, especially at frequencies above \text10 kHz. Results also reveal \text23.4\% difference between \text0.5 and \text3 mm thicknesses at \text1 kHz , while the difference is \text3.5\% at \text5 MHz. Moreover, experimental results demonstrate agreement between the simulated and actual performances. Measurements confirm that using \text16 GA off-the-shelf carbon steel sheets with \text80\% perforation, an average shielding effectiveness of \text40 dB is achieved. [ABSTRACT FROM PUBLISHER]