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An inverse matrix auto-search algorithm for radiated two-stage (RTS) multiple-input and multiple-output (MIMO) over-the-air (OTA) tests is proposed in this paper. The RTS method is one of the significant techniques for the MIMO OTA test and was provided by organizations such as the Cellular Telecommunication and Internet Association and the Third-Generation Partnership Project. An extremely important basic step in the RTS test procedure is to select an appropriate combination of measurement antennas and device-under-test orientation for inverse matrix solving. The automatic resolving algorithm proposed in this paper can be divided into two parts: the technique for selecting the appropriate combinations for inverse matrix solving, and the method for solving the inverse matrix at a fixed combination. The technique proposed in this paper can make the RTS test procedure automatic and fast, which greatly improves the user experience. The most mentionable advantage of the technique is that only 2 min are required for the whole process including the appropriate combination calculation and the inverse matrix solving at the selected combination, while several hours might be needed using the traversal method. [ABSTRACT FROM PUBLISHER]

The papers in this special section are focused on one aspect of the current technological wave. As we all know, nature-inspired (NI) computing and algorithms play an ever increasing role in problem solving by way of optimization, machine intelligence, data mining, and resource management. Nature has evolved over millions of years under a variety of harsh and severe environments and, thus, provides a rich source of inspiration for designing algorithms and approaches to tackle real-world challenging EMC and Signal & Power Integrity (SI/PI) problems. [ABSTRACT FROM AUTHOR]

A hybrid analytical/numerical conducted an electromagnetic interference (EMI) modeling approach, which adopts both numerical method and analytical method, is proposed in this paper. In this model, the noise source is calculated directly with the original data from oscilloscopes. The noise path at different operating status is extracted from the original converter topology and its analytical expression is then derived. Also, according to the EMI receiver detector mode, the algorithm of the EMI receiver is proposed in this paper. Peak (PK), average (AV), and quasipeak (QP) values of the EMI can then be calculated to analyze the impact of each relevant component. The analytical method is provided to carry out PK, AV, and QP simulations accurately and fast. The simulation and experimental results for common mode leakage currents validate this EMI model. Furthermore, two analysis examples are given to illustrate how this model is applied for engineers. [ABSTRACT FROM AUTHOR]

In this paper, a fast adaptive cross approximation (FACA) algorithm and the characteristic basis function method (CBFM) are presented to accelerate the computing processing in using the multiscale compressed block decomposition (MS-CBD) method in direct solutions of electrically large problems. The impedance matrix or the reduced matrix can be compressed into block matrices of the MS-CBD structure using the FACA. With the recursive inversion processes on the reduced matrix, it is easy to obtain the solutions. Combined with the fast adaptive cross sampling and the matrix decomposition algorithm method, the speed of the calculation of FACA is proved much faster than that of the conventional adaptive cross approximation. The numerical results of several perfect electric conducting objects are validated to demonstrate the performance of this method. The simulation results show that the computational time of the proposed method is much less than the conventional MS-CBD method with the CBFM, while their computational storages are similar. [ABSTRACT FROM AUTHOR]

In a high-speed digital communication system, jitter performance plays a crucial role in bit-error rate. It is important to accurately derive each type of jitter as well as total jitter and to identify root causes of jitter by jitter decomposition as a key tool. In this paper, we extend our previously reported algorithm to decompose duty cycle distortion as well as other deterministic jitter components including periodic jitter (PJ), intersymbol interference (ISI), and random jitter (RJ), and describe more detail of this algorithm with extensively simulation and measurements to verify the algorithm. The proposed ISI model only requires the time invariant condition, which is true for almost all systems, while the traditional ISI model is valid only with linear time invariant assumption. Compared to the conventional methods, the proposed jitter decomposition method is able to obtain estimated individual jitter component values with good accuracy by using fewer samples of total jitter data. The efficiency and accuracy of the proposed method were demonstrated by simulation and hardware experiments. [ABSTRACT FROM AUTHOR]

Optimally designed arrays are used to obtain high gain and directivity. Based on the desired application, different radiation patterns can be generated. These patterns have generally a main beam and some sidelobes. These last ones are undesirable because they can cause electromagnetic interference and compatibility issues. Therefore, sidelobe levels (SLLs) reduction is one of the most important factors for the design of antenna arrays and arrays must be designed in a way to reduce SLLs. In this paper, the optimal design of circular antenna arrays (CAA) for maximum SLLs reduction is investigated using a newly developed metaheuristic that is the most valuable player algorithm. This algorithm is inspired from sport and it has been proven to be an excellent optimization algorithm for mathematical benchmarks. Three cases with different number of arrays are investigated. For comparison purposes, ten other well-known optimization algorithms are used. The design results obtained show the superiority of the proposed algorithm for the optimal design of CAA and for sidelobe reduction over many other algorithms. [ABSTRACT FROM AUTHOR]

This paper investigates the application of support vector machine to the modeling of high-speed interconnects with largely varying and/or highly uncertain design parameters. The proposed method relies on a robust and well-established mathematical framework, yielding accurate surrogates of complex dynamical systems. An identification procedure based on the observation of a small set of system responses allows generating compact parametric relations, which can be used for design optimization and/or stochastic analysis. The feasibility and strength of the method are demonstrated based on a benchmark function and on the statistical assessment of a realistic printed circuit board interconnect, highlighting the main features and benefits of this technique over state-of-the-art solutions. Emphasis is given to the effects of the initial sample size and of input noise on the model estimation. [ABSTRACT FROM AUTHOR]

In this paper, a novel algorithm that selects optimal paths for conducting automated near-field (NF) measurements is presented. The resulting dataset of measurements can then be used to model the complete NF electromagnetic emissions of an electronic device or predict the far-field emissions. The models obtained using the training sets generated with the aid of the proposed algorithm are substantially more accurate compared to existing point-based methods. The algorithm is validated by comparing it against an earlier adaptive sampling algorithm that optimizes point-based measurement datasets. [ABSTRACT FROM PUBLISHER]

This paper deals with the susceptibility of electronic units to radiated electromagnetic (EM) interference and specifically, it focuses on the parasitic coupling of EM fields with printed circuit board interconnects like microstrip lines. To this purpose, a uniform lossless microstrip line illuminated by an EM plane wave is considered and the voltages at the line terminations are evaluated referring to the Baum–Liu–Tesche equations. Based on this, a new algorithm to identify, frequency-by-frequency, the incidence angles and the polarization of the impinging field that gives rise to the maximum induced voltages at the line terminations is presented. [ABSTRACT FROM AUTHOR]

It is very essential to calculate the mutual impedance between overhead and buried conductors for analyzing electromagnetic compatibility problems related to a transmission line system. An efficient algorithm for calculating the Pollaczek integral, whose integrand oscillates rapidly and decays slowly, is proposed in this paper. With the help of the asymptotic extraction technique, the Pollaczek integral can be decomposed into the sum of two parts, one of which is expressed with an exponential integral and the other is the one that has a rapidly damped integrand. A comparison of the numerical results with published data shows very good agreement. The proposed approach is a good candidate for calculating impedances related to the Pollaczek integral. [ABSTRACT FROM AUTHOR]

Most lightning location networks are based on real-time analytical solutions of certain simplified models, while the reality is much more complicated. In this paper, we introduce a graphics processing unit (GPU)-based parallel computing algorithm that can extensively benefit lightning geolocation networks. For a network running this GPU-based algorithm, one can build up a geolocation database based on numerical solutions of certain complete models in advance, and lightning geolocations can then be easily determined with a grid-searching technique in real time. One such grid-searching technique, is the grid traverse algorithm (GTA) for the traditional time of arrival technique. By running GPU-based GTA in a six-station two-dimensional (2-D) and a five-station 3-D networks, we show that extremely high network performance can be achieved, with a processing speed of about 2700 times faster than CPU-based GTA. The location accuracy of GPU-GTA is examined with Monte Carlo simulations, showing that GPU-GTA can locate a lightning source in real time with high accuracy. We also find that when the grid step is comparable with the inherent time uncertainty of a network, the location accuracy cannot be improved further with a finer grid step. [ABSTRACT FROM AUTHOR]

Aerial and buried electric conductors often share the same right of way. When a phase-to-ground fault occurs, high transient-induced overvoltages appear from short-circuit currents to the ground. The mutual ground-loop impedances between both systems are given by the Pollaczek coupling integral that does not possess an analytic closed-form solution, and its integrand is highly oscillatory to perform a direct numerical integration. An efficient and accurate algorithmic evaluation of the Pollaczek coupling integral is presented in this paper. The obtained result is used in the numerical assessment of approximated formulas previously issued by Lucca, Wedepohl, and Comité Consultatif International Téléphonique et Télégraphique. [ABSTRACT FROM AUTHOR]

This paper presents the adaptive cross approximation (ACA) algorithm to reduce memory and CPU time over- head in the method of moments (MoM) solution of surface integral equations. The present algorithm is purely algebraic; hence, its formulation and implementation are integral equation kernel (Green's function) independent. The algorithm starts with a multilevel partitioning of the computational domain. The interactions of well-separated partitioning clusters are accounted through a rank-revealing LU decomposition. The acceleration and memory savings of ACA come from the partial assembly of the rank-deficient interaction submatrices. It has been demonstrated that the ACA algorithm results in 0 (NIogN) complexity (where N is the number of unknowns) when applied to static and electrically small electromagnetic problems. In this paper the ACA algorithm is extended to electromagnetic compatibility-related problems of moderate electrical size. Specifically, the ACA algorithm is used to study compact-range ground planes and electromagnetic interference and shielding in vehicles. Through numerical experiments, it is concluded that for moderate electrical size problems the memory and CPU time requirements for the ACA algorithm scale as N4/3logN. [ABSTRACT FROM AUTHOR]

This paper discusses a method for the construction of multiport broadband passive macromodels using frequency data obtained from an electromagnetic simulation or measurements. This data could represent the frequency response of a distributed interconnect system. The macromodels are generated using rational functions by solving an eigenvalue problem. For numerical computation, the macromodels are represented as a summation of rational functions consisting of low-pass, band-pass, high-pass, and all-pass filters. The stability and passivity of the macromodels are enforced through constraints on the poles and residues of rational functions. To enable the construction of broad- band macromodels, methods based on band division, selector, subband reordering, subband dilation, and pole replacement have been used. Two test cases that describe the performance of the proposed algorithm, and three test cases that are representative of distributed systems have been analyzed to verify the efficiency of the method. [ABSTRACT FROM AUTHOR]

One of the chief challenges of the finite-difference time-domain (FDTD) subgridding algorithm is developing a field-coupling scheme to avoid late-time instability resulting from spatial interface between regions with different meshes. This paper introduces the concept of the nonuniform grid method to appropriately handle the tangential electric component on the spatial interface of the two meshes. This study analyzed shielding effectiveness of metallic enclosures with apertures. A novel subgridding algorithm was employed to locally refine the region containing a thin perfect electric conducting (PEC) film with apertures through FDTD simulation. Image theory was implemented to obtain an interpolation scheme of the magnetic fields as the sub-boundary surface when a thin PEC film traverses the subgridding interface. The numerical accuracy and stability of the proposed method were verified by comparing with results from other established methods. [ABSTRACT FROM PUBLISHER]

In this paper, an adaptive hierarchical sparse grid collocation (ASGC) method combined with the discontinuous Galerkin time-domain method is leveraged to quantify the impacts of random parameters on the electromagnetics systems. The ASGC method approximates the stochastic observables of interest using interpolation functions over a set of collocation points determined by the Smolyak's algorithm integrated with an adaptive strategy. Instead of resorting to a full-tensor product sense, the Smolyak's algorithm constructs the collocation points in a hierarchical scheme with the interpolation level. Enhanced by an adaptive strategy, the Smolyak's algorithm will sample more points along important dimensions with sharp variations or discontinuities, resulting in a nonuniform sampling scheme. To flexibly handle different stochastic systems, either piecewise linear or Lagrange polynomial basis functions are applied. With these strategies, the number of collocation points is significantly reduced. The statistical knowledge of stochastic observables including the expected value, variance, probability density function, and cumulative distribution function are presented. The accuracy and robustness of the algorithm are demonstrated by various examples. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate the computational affordability and accuracy of a leap-frog discontinuous Galerkin (LFDG) time-domain method for high intensity radiated fields assessment in electromagnetic compatibility for aerospace. The conformal truncation of the computational domain is discussed and formulated in the LFDG context. Numerical validations are performed on challenging test cases, in comparison to measurements and to other numerical methods, demonstrating the accuracy, efficiency, and scalability of the algorithm. [ABSTRACT FROM PUBLISHER]

In this paper, fast capacitor assignment algorithms capable of finding a decoupling solution scheme with a minimum number of components that meets a predefined target impedance with a semi-arbitrary shape within a few seconds to an hour for a given power distribution network (PDN) are proposed. The proposed algorithms also provide identification of shadowed decap ports in a PDN based on an inductance matrix extraction from the given PDN model. Elimination of those shadowed decap ports with the proposed algorithms enables more effective layouts and cost savings on PCB designs. [ABSTRACT FROM PUBLISHER]

In this paper, a novel mapping algorithm by applying electromagnetic time reversal (EMTR) technique to broadband very high frequency (VHF) for the direction-of-arrival (DOA) estimation of lightning radiation sources is proposed and validated. Based on the theory of array signal DOA estimation and time reversal (TR) principle, the lightning radiation receiving model with broadband VHF array is established, and thereafter the TR synthesized signal for arbitrary direction is derived. It is proved that the direction with the maximum norm of synthesized signal is the optimal estimation for the incident direction, and hence the procedure for the EMTR-VHF method is derived. Numerical simulations are conducted for testing the algorithm and investigating the relationships between the array spatial resolution and the available signal frequencies, robustness of the algorithm, et al. Two metrics, amplitude ratio and energy ratio, are devised to filter false locations, and the acceptable ranges of them are further estimated by simulation. In order to further validate the EMTR-VHF algorithm, field experiments are carried out. The results show that the EMTR-VHF method performs well, especially for the sources with low elevations, with the error less than 1°. Finally, the application of EMTR-VHF method in locating a negative cloud-to-ground flash is presented. Temporal and spatial development of the leader-return stroke sequence could be well depicted. The results are generally consistent with the VHF interferometry technique, which confirm its ability in lightning localization. Besides, the discrepancy between this algorithm and broadband interferometry method are documented. [ABSTRACT FROM PUBLISHER]

In this paper, thermal breakdown effects in a laterally diffused MOS (LDMOS) FET under the impact of high-power microwave (HPM) pulses are investigated by theoretically analyzing, modeling, and measuring. Experimental investigations of the LDMOS FET-based power amplifier (PA) are performed under different pulse durations. The measurement system consists of an adjustable HPM source, one controller, couplers, limiters, attenuators, one four-channel oscilloscope, and a DUT. By increasing the input pulse power level, electrothermal breakdown is observed. The breakdown temperature is calculated by using a 2-D analytic model based on the measured power to failure data. Then, our developed time-domain finite-element numerical algorithm is used to characterize temperature distribution and transient performance of the LDMOS FET. The energy capability, which defines the maximum energy that the device can handle, is 15.5 mJ under the pulse duration of 1 ms with a breakdown temperature of 605 K. [ABSTRACT FROM PUBLISHER]

In this paper, an efficient reciprocity-based algorithm is proposed to predict the worst case voltages and currents induced by external plane waves at the ports of a multiconductor transmission-line system. The proposed algorithm consists of two main steps. In the first step, the far-field radiation of the multiconductor transmission-line system is fully characterized by a minimal number of full-wave simulations. In the second step, this information is used to efficiently evaluate the voltages and currents induced by a plane wave with arbitrary angles of incidence and polarization. After this, their worst case values can be easily found. The main advantage of the proposed algorithm is that no new full-wave simulations are required if different incoming plane waves or different sets of terminations at the ports of the multiconductor transmission-line system are to be considered. [ABSTRACT FROM AUTHOR]

The electromagnetic fields generated by a vertical electric dipole, expressed in the form of the Sommerfeld integral, are important in the study of lightning. In this paper, an algorithm, which can analytically approximate the Sommerfeld tail integral, is proposed. Due to the fact that the tail integral is expressed by a sum of several error functions, the tail integral of a vertical electric dipole can be evaluated without the truncation of the infinite upper limit. The comparison indicates that the results calculated by the proposed algorithm are accurate, and the computational time, compared to the one using direct numerical quadrature method, is much shorter. [ABSTRACT FROM AUTHOR]

The evaluation of the electromagnetic field radiated by a lightning stroke is of essential importance for the study of the interaction between lightning electromagnetic fields and power lines, or other sensitive installations. A fast algorithm for calculating the fields generated by a vertical electric dipole over a lossy ground, which can be expressed by the well-known Sommerfeld integrals, is presented in this paper. The integrals are decomposed into two parts. One part can be calculated by a recursive analytical expression, and the other part can be evaluated numerically due to the fact that the extracted integrand damps rapidly with the help of the asymptotic extraction technology. A comparison with some approximate formulas is performed in detail with variable parameters, such as the soil parameters, the geometry, and the excitation frequency of dipole, which shows very good agreement as far as the lightning field is concerned. The technical merit of the proposed approach is its universality, which can be applied for arbitrary parameters, and its computing time is still competitive. [ABSTRACT FROM AUTHOR]

An automated procedure for modeling the radiated emissions of electronic devices is presented in this paper. The principle of the model is to replace the device by a set of electric dipoles defined by their positions, orientations, lengths, and currents. Thus, this modeling procedure aims to determine the number of dipoles and their parameters with a minimum user intervention. The procedure is divided into three parts: the near-field measurements of the tangential components of the magnetic field, an image processing to obtain the number of sources of the model, and the application of an optimization algorithm in order to obtain the different parameters of the model, such as the current and the position of each source. [ABSTRACT FROM AUTHOR]

In this paper, a local multilevel fast multipole algorithm (LMLFMA) based on an improved electric field integral equation (IEFIE) is developed to achieve fast and efficient solu. tion of electromagnetic scattering from 3-D conducting structures, The IEFIE is used to reduce iteration number, and LMLFMA is applied to further accelerate the computation of matrix-vector multiplications in iteration, in which only the local interaction between subscatterers are taken into account. Numerical results show that the present method attains faster iterative convergence than traditional EFIE and less computational cost than MLFMA, The speedup can achieve at least 4-5 times while keeping an rms error, of less than 2 dB [ABSTRACT FROM AUTHOR]

This paper is devoted to the comparison between different criteria used to evaluate the functioning of a mechanically stirred reverberation chamber. Usual criteria based on power or electric fields are considered, and we also propose a criterion based on the Kolmogorov-Smirnov test, called in this paper "success ratio to Kolmogorov-Smirnov test" (SRKS). The SRKS represents the acceptation ratio of this test applied at several points of the working volume, when considering a field component and its associated theoretical distribution. After a presentation of the criteria and of the studied chamber, data issued from 3-D finite-difference time-domain simulations and measurements are used to analyze the chamber functioning by the use of these criteria. This study is performed on a large frequency band, in the lossless case as well as with a lossy chamber, and for several stirrer shapes, to emphasize the influence of these parameters. The comparison of the usual criteria with the SRKS shows the SKRS is an accurate test to estimate the lowest usable frequency of a given reverberation chamber. [ABSTRACT FROM AUTHOR]

This paper presents a new algorithm for simulating electromagnetic (EM) field coupling with nonuniform multiconductor transmission lines in a circuit simulation environment. The proposed algorithm is based on the concept of passive model-order reduction, whereby an algorithmically developed passive reduced-order model, coupled with a set of equivalent sources representing the incident filed, are shown to accurately capture the behavior of the transmission line under EM excitation. The reduced-order model is developed independently from the particular shape of the incident field pulse, in the sense that, in constructing the model, one does not need prior knowledge about the waveform of the incident pulse of the EM field. In addition, it is also shown that the model developed can be used to simulate the transmission line in the absence of the EM field. The derived equivalent sources, representing the field coupling, are given directly in the time domain, thereby making simulation under nonlinear circuit terminations an easy task. Although the proposed work is aimed mainly at simulating nonuniform transmission lines, it can be applied to uniform lines as a special case. The proposed algorithm has been validated numerically with several examples. [ABSTRACT FROM AUTHOR]

This paper deals with the identification of low-order accurate macromodels describing electrically long lossy multiconductor transmission lines. The formulation is based on the generalized method of characteristics, whose key feature is the extraction of delays from the propagation operators. We describe and compare different delay extraction approaches, in view of the identification of the macromodels. In particular, we propose a new identification procedure enhancing the results coming from a vector fitting algorithm by a further nonlinear identification step. This gives more general properties to the model implementation (e.g., a state space realization with no repeated pole), possibly improving the accuracy at the same time. Some reference case studies are analyzed to highlight the key features of the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper, a novel improved electric field integral equation (IEFIE) is developed to achieve fast and accurate solution of electromagnetic scattering from 3-D conducting structures. By adding the principle value term of the magnetic field integral equation (MFIE) operator into the EFIE operator, a well-conditioned improved EFIE operator is constructed. To achieve a reasonable accuracy, several update steps for the current vector are required. A multilevel fast multipole algorithm (MLFMA) is also applied to accelerate the computation of matrix-vector multiplications in the iteration. The present method attains much faster convergence of iterations than traditional EFIE and much better accuracy of the solution than the traditional combined field integral equation, particularly for 3-D structures with open or sharp surfaces. Numerical results show the validity and efficiency of the present method. [ABSTRACT FROM AUTHOR]

The number of power installations lying underground has been increasing in the last few years, and such devices are very sensitive to the effect of the lightning electromagnetic fields, due to the massive presence of power electronics. As a consequence, the scientific community has devoted much effort in the direction of a more accurate modeling of underground lightning fields and their coupling to cables. The exact expressions of the underground lightning fields have been derived by Sommerfeld decades ago. However, their numerical evaluation has always been a hard task because of the presence of slowly converging improper integrals. In the past, some approximate formulas have been derived, which have been included in field-to-transmission line coupling models to estimate the effect of lightning on buried cables. In this paper, an efficient algorithm for the evaluation of the Sommerfeld expression for underground fields is presented, and its mathematical features are discussed. The numerical treatment of the Sommerfeld integrals is based on a proper subdivision of the integration domain, the application of the Romberg technique, and the definition of a suitable upper bound for the error due to the integral truncation. The remarkable efficiency in terms of CPU time of the developed algorithm makes it possible to use it directly in field-to-buried cable coupling simulation codes. Finally, the developed algorithm is used to test the validity of the Cooray's simplified formula for the computation of underground horizontal electric field. It is shown that predictions of the Cooray's formula are in good agreement with exact solutions for large values of ground conductivity (0.01 S/m). However, for poor conductivities (0.001 S/m or so), Cooray's expression yields less satisfactory results, especially for the late time response. [ABSTRACT FROM AUTHOR]

The eigenmode expansion method (EEM) is a convenient technique for characterizing a power/ground (PIG) plane pair structure. The requirements of the plane pair's shape, however, and a double-infinite series in its equation limit its applications. To overcome its disadvantages and extend its applications, this paper proposes some techniques for the EEM and makes some modifications to it. First, by employing the newly presented inverted composition method and the segmentation method, the improved EEM can be used to characterize a holey P/G plane pair with irregular shapes. Second, by employing a trigonometric Fourier series and a particular Pade approximation method-the η-algorithm, the double-infinite series in EEM can be changed into a single one and its convergence can be accelerated apparently so that the cornputation efficiency of the EEM is greatly improved. An example is considered to compare the numerical data of the new EEM with corresponding measurement results, thus demonstrating the good accuracy. The computation time of the proposed method is compared with that of the finite-element method (FEM), which shows that the new method has higher efficiency. [ABSTRACT FROM AUTHOR]

A subcell model for thin wires in the finite-difference time-domain (FDTD) method using modified telegraphers equations has been developed by Holland et al. Edelvik has previously presented an extension of their algorithm, which allows for arbitrarily located and oriented wires with respect to the Cartesian grid. This is important to be able to accurately model wires that cannot be aligned to the Cartesian grid, e.g., tilted wires and circular loop wires. Recently, a dual set of equations has been proposed for modeling of thin slots. In this paper, we show that using a similar algorithm as for thin wires we can also handle slots of arbitrary location in Cartesian planes. Previous thin slot models have been susceptible for instabilities. We show that a symmetric coupling between field and slot yields a stable time-continuous field-slot system and that the fully discrete field-slot system is stable under a generalized Courant-Friedrich-Lewy (CFL) condition. The proposed method is demonstrated for scattering from a finite-length slot in an infinite conducting wall and a shielding enclosure including a slot. The results are in good agreement with published experimental data. [ABSTRACT FROM AUTHOR]

Near-field scanning with phase measurement is always a challenge in practical experiments because of its complexity and lack of accuracy. Therefore, utilizing the magnitude-only information to achieve phase-retrieval and emissions source reconstruction is preferred. This paper proposes a fast and accurate algorithm that can model the emissions from ICs by generating a set of equivalent dipole elements. The process of this algorithm only requires the information of the field magnitudes on two near-field scanning planes of different heights. Unlike other conventional source reconstruction techniques (such as genetic algorithm, gradient optimization), the proposed approach iteratively performs the back-and-forth transformations among the fields and equivalent dipole elements. By optimizing the locations of the equivalent dipole array and the initial values of these dipole elements, the iteration process is capable of quickly converging to the correct electromagnetic field values, including both magnitude and phase. The fields recovered from the calculated equivalent dipole sources have been validated by comparing to the fields emitted from a practical IC source. [ABSTRACT FROM PUBLISHER]

Recent studies have shown high interest in statistical methods dedicated to the prediction of the maximum confidence levels in simulations and measurements for risk assessment in electromagnetic compatibility. In particular, it has been shown that one of the main issues remains the access to a number of samples allowing the assessment of the risks in regards to test setup random variables. In this paper, it is argued that a real-time bootstrapping module enables to optimize the number of experiments while estimating the maximum confidence levels of the accessible samples. An efficient technique is presented to substitute the full experimental requirements to a simple and low time-consuming mathematical algorithm. The benefits expected of this method are illustrated throughout experimental shielding effectiveness power measurements. Based upon an optimized statistical approach, the first statistical moments (e.g., mean and standard deviation) of power received inside a cabinet are provided jointly with an accurate assessment of power's quantiles, leading to a better evaluation of extreme values. [ABSTRACT FROM AUTHOR]

This paper describes the application of a new and easy to implement algorithm to EMI near-field scanning measurement results obtained with a time-domain-based measurement system. The algorithm aims to reduce the effect of spectral leakage on amplitude and phase of the measured field components. The proposed algorithm significantly increases the accuracy of the measured electromagnetic near field with a limited extra computational cost. The versatility and effectiveness of the proposed algorithm is shown on both simulated and measured data. It is shown that for situations with one single frequency component or with several well-separated frequency components, the algorithm is as performant as the application of a flat top window and outperforms other types of windows. However, as soon as the frequency components approach each other implying their spectral leakage patterns overlap, the proposed algorithm outperforms the application of a flat top window. [ABSTRACT FROM AUTHOR]

This paper focuses on two special aspects regarding fast partial inductance computations in the nonorthogonal partial element equivalent circuit (PEEC) method. First, a multifunction PEEC algorithm is proposed, which is able to calculate partial inductances as efficient as possible for mixed environments with nonorthogonal as well as orthogonal cells. Second, a new numerical integration routine for the self-inductance terms of nonorthogonal cells is focused on by using averaged orthogonal subelements. It is presented that the slow convergence caused by the singularities is avoided and a fast evaluation of the self-terms is enabled consequently. The approach is verified by two examples where a good agreement is obtained when comparing the proposed results with analytical solutions as well as finite-element method reference results. [ABSTRACT FROM AUTHOR]

Electronically initiated explosives can have unintended electromagnetic emissions, which propagate through walls and unshielded containers. These emissions, if properly characterized, can be used to quickly detect explosive threats. In this paper, an analytic model is developed for the unintended emissions of clocked digital devices, such as microcontrollers, which can be used as initiators. It is demonstrated that these emissions are clock-dependent, periodic train of impulses. An autoregressive model of these clock emissions is developed, and the model is validated using measurements of an 8051 microcontroller. Existing algorithms, including pitch-estimation and the epoch-folding algorithm, are surveyed for detecting generic digital devices with unknown clock frequencies and emissions characteristics. A novel detection algorithm, which uses pitch estimation, is proposed. The model is used, in a simulated environment, to evaluate the noise performance of the proposed algorithms. Results indicate that the pitch-estimation techniques are robust against jitter and have a 4-dB sensitivity improvement over epoch-folding algorithms. [ABSTRACT FROM AUTHOR]

This paper presents a time-domain macromodel for lossy multiconductor transmission lines exposed to electromagnetic interference. The proposed algorithm is based on the recently developed passive method of characteristics, which provides an efficient mechanism to ensure the passivity of the macromodel for different line lengths. Numerical examples illustrate that when compared to other passive incident field coupling algorithms, the proposed method is efficient in modeling electrically long interconnects since delay extraction without segmentation is used to capture the frequency response. [ABSTRACT FROM AUTHOR]

Presents corrections to the paper, “Propagation along thin conductors parallel to interfacing homogeneous half-spaces,” (Pawlik, B., et al), IEEE Trans on Electromagnetic Compatibility, vol. 60, no. 1, pp. 266–275, Feb. 2018. [ABSTRACT FROM AUTHOR]

In this paper, an unconditionally stable finite-difference time-domain algorithm is presented for analysis of lossy nonuniform multiconductor transmission line (MTL). The results of the proposed algorithm are confirmed by those of the Leap-Frog algorithm. The unconditionally stable algorithm alone cannot decrease the time consumption, especially when the MTL is excited by modulated signals. The complex phasor transformation approach is used to separate the modulating signal from the carrier signal when an MTL is excited by a modulated signal. A new set of equations is generated using this approach. The new equations are based on the modulating signal, and the carrier signal is eliminated in these equations. The derived equations are solved by Leap-Frog algorithm, and the results confirm the accuracy of these equations. Finally, the proposed equations are solved by the unconditionally stable algorithm at several temporal step sizes. The results indicate that this method has much lower CPU time compared with the conventional method and also has a very good accuracy. [ABSTRACT FROM AUTHOR]

Shielding effectiveness (SE) of metallic structures with thin slots can be analyzed by using finite-difference time domain (FDTD) method. However, the arbitrarily shaped thin slots make the calculation be unbearable or even worse. To improve the computational efficiency, contour path (CP) algorithm is thus extended to be applied to the calculation of complex thin slots using FDTD. An equivalent model is proposed to simplify the CP-FDTD calculation for thin slots with complex penetrating paths formed by overlapped joints or flush-mounted aperture panels. It is validated by the good accordance of SE obtained using conventional fine-cell FDTD for different kind of slots with various penetrating paths. The SE prediction accuracy in terms of incident wave and the ratio of slot width to Yee's cell size are investigated. The physical measurement of SE of a metallic enclosure with thin slots is conducted and its results are in a good agreement with that obtained by using extended CP-FDTD. [ABSTRACT FROM AUTHOR]

One of the most popular techniques to take into account the finite ground conductivity in the evaluation of the radial component of the electric field generated by a lightning return stroke is the Cooray–Rubinstein (CR) formula. As this formula is derived in the frequency domain, its application in time-domain simulation codes for the analysis of lightning-induced overvoltages on overhead lines might be challenging. In this paper, two methods allowing a simple time-domain implementation of the formula are discussed. The first one is an enhanced version of an algorithm recently proposed by two of the authors, while the second consists of a new technique, based on a suitable rational approximation of the impedance term appearing in the CR formula. This second approach is characterized by an intrinsic easiness in time-domain implementation and a considerable computational efficiency compared with conventional methods. [ABSTRACT FROM PUBLISHER]

This paper proposes a simple, fast, and accurate method for calibrating the free-space antenna factors of broadband electromagnetic compatibility (EMC) antennas. This method adopts a fixed-height calibration configuration and a multiple-signal-classification-based (MUSIC) data processing algorithm. Because this configuration does not require height scans, it significantly shortens measurement time and removes height-dependent calibration errors. In addition, the MUSIC-based data processing algorithm can remove unexpected reflections from the ground plane or any other reflecting objects, and transfer calibration into the free-space transmission model, from which the free-space antenna factors are obtained. The algorithm of this method can also automatically compensate for the phase center shift, which makes measurement easier and more convenient. To verify this method, numerical simulations for half-wave dipoles and experimental measurements for log-periodic dipole array (LPDA) and horn antennas are conducted. The simulated results for the half-wave dipoles indicate that the error from the theoretical \AFFS can be within ±0.5 dB. In the case of the experimental measurements, the calibrated results are compared with other published standard methods: the mean differences can be as low as 0.25 dB for the LPDA, and as low as 0.36 dB for the horn antennas. The good agreement between results confirms that the proposed method can yield accurate estimations of free-space antenna factors for broadband EMC antennas. This method also provides a new alternative for obtaining fast and accurate antenna calibration. [ABSTRACT FROM PUBLISHER]

This paper describes a block-latency insertion method (LIM) for the fast transient simulation of the large networks with many coupling elements. First, the basic formulation of LIM is reviewed. Next, the block-LIM formulation for the network with many coupling elements, such as the mutual inductance, the mutual capacitance, and controlled sources is described. Then, the block-LIM algorithm is applied to the tightly coupled transmission lines, which are connected to each other by a number of mutual inductors and capacitors. Finally, some numerical results are shown, and it is confirmed that the proposed technique is useful and efficient for the simulation of the tightly coupled transmission lines. [ABSTRACT FROM AUTHOR]

Radiated fields of unintentional radiators can be estimated from the measurements performed by a transverse electromagnetic cell. A hybrid coupler connected to the outputs of the transverse electromagnetic cell separates the electric and magnetic coupling, which allows to calculate the generated far-field radiation consistently. However, the transverse electromagnetic cell and the hybrid coupler are mismatched. The mismatch introduces an error in the measured data. The error of up to 8.5 dB is obtained in the measurements of the small loop. The impedance mismatch is dominantly a consequence of the phase shift, which is related to the propagation of the signal through the measurement setup and which is present even if all elements of the measurement setup are ideal. The methodology for correcting the measured data is proposed and it is validated on the measurements of the small loop. The methodology is applied to the measurements of two synchronous buck converters and their radiated fields are estimated. [ABSTRACT FROM AUTHOR]

This paper proposes an improvement for the standard algorithms used to correlate the radiated emission measurements performed in a gigahertz transverse electromagnetic (GTEM) cell to measurements performed at an open area test site (OATS). The improvement compared with standard correlation algorithms lies in the ability to use literally all data measured. This is achieved by using nonlinear regression models in order to estimate the amplitudes of a multipole model. Assuming equally phased dipole moments and using nine measurements, numerical simulations indicate significant superiority of this new algorithm in comparison to the standard approach. The results can be improved further by using additional measurements. The simulation results show strong evidence that the algorithm also provides precise results for the amplitudes, if not all components of the dipole moments are in phase. Experiments with a real-world test object further validate the method. [ABSTRACT FROM AUTHOR]

High-speed interconnects are increasingly becoming susceptible to electromagnetic interference (EMI). Hence, there is a growing need for fast simulation of interconnect lines in the presence of incident field coupling using circuit simulators such as SPICE. However, the presence of a large number of coupled lines in modern interconnect structures is a serious limiting factor in these simulations. In order to simultaneously address these difficulties, a new algorithm is presented in this paper for EMI analysis of large number of coupled interconnects. The new method exploits the recently developed waveform relaxation (WR) and transverse partitioning algorithms for fast EMI analysis. The same WR sources that are computed for multiconductor transmission line analysis are also employed for EM! analysis. The computational complexity of the proposed EMI analysis grows only linearly with the number of lines. In addition, the algorithm lends itself to parallel implementation leading to further reduction in CPU time. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine a robust prediction algorithm that can be used to correct the measured specific absorption rate (SAR) in a homogeneous phantom when its complex permittivity deviates from standardized reference values. Results are analyzed over a frequency range of 30-6000 MHz. Both measurements and numerical simulations are presented. Several antenna sizes and distances to the phantom are investigated so as to study a large range of SAR distributions. It is demonstrated that the prediction algorithm, while developed using dipole antennas, also works well for mobile telephone models. Employing the prediction algorithm reduces the SAR measurement uncertainty, thereby improving the reproducibility of SAR compliance assessment between laboratories. Another benefit of the algorithm is that it enables the use of broadband tissue-equivalent liquids, whose dielectric parameters are not currently within the tight tolerances of existing standards. The use of broadband liquids reduces the cost of SAR measurement. The method presented in this paper is of benefit to the IEEE 1528 and IEC 62209 measurement standards. [ABSTRACT FROM AUTHOR]

Abstract-In this paper, we propose a high-resolution time frequency-domain reflectometry technique as a methodoIogy of detection and estimation of faults on a wire. This method adopts the time-frequency cross-correlation characteristics of the observed signal in both the time and frequency domains simultaneously. The accuracy of the proposed method is verified with experiments using a radio-guide-type coaxial cable and comparing it with traditional time-domain as well as frequency-domain reflectometry methods. It is clearly shown here that the proposed algorithm produces excellent results compared to the conventional methods for single as well as multiple fault cables. [ABSTRACT FROM AUTHOR]

In this paper, we extend an existing heuristic algorithm for fixed-frequency assignment in cellular communication networks in order to account for the effects of adjacent channel interference (Act). Our algorithm utilizes estimations of carrier-to-interference ratio instead of binary channel separation constraints. The extended algorithm avoids Overoptimistic frequency assignments that do not guarantee interference-free operation environments. Its cost is the increased computational complexity. We estimate the upper bound of the algorithm's complexity when ACI is taken into account. Simulations demonstrate that despite the theoretical high increase in complexity, the algorithm is suitable even for a quasi-dynamic frequency assignment scheme in practical situations. The algorithm enhances the spectrum utilization in cellular networks while reducing harmful interference. [ABSTRACT FROM AUTHOR]