Electromagnetic Compatibility Applications Research Articles

Efficient Krylov‐based 3D FVTD schemes with adaptive domain decomposition for graphene and nanostructured EMC components

SummaryThe rigorous design of arbitrarily shaped graphene and nanocomposite structures in realistic electromagnetic compatibility applications is presented in this paper by means of a combined finite‐volume time‐domain methodology. The new 3D formulation proposes a set of adjustable‐order derivative approximators in general curvilinear coordinates and an adaptive domain decomposition to attain effective field flux representations of electromagnetic fields in areas with subwavelength attributes or infinitesimally thin wiring. Also, a fully passive reduced order macromodelling scheme, based on the Krylov truncation, is developed for the significant decrease of the state‐space transfer matrix order, particularly when finite graphene sheets are to be analyzed. A key asset is that the necessary basis for the Krylov space is retrieved from a framework of weighted Laguerre functions, which do not require laborious orthogonalizations. Hence, highly accurate and economical discretizations with minimized dispersion errors are obtained. Numerical outcomes, addressing elaborate comparisons with reference data, from various nanostructured electromagnetic compatibility arrangements, certify the benefits of the featured technique, accelerated via graphics processing units and unveil its applicability.

A Modular Test-Suite for the Validation and Verification of Electromagnetic Solvers in Electromagnetic Compatibility Applications

Computational solvers are increasingly used to solve complex electromagnetic compatibility (EMC) problems in research, product design, and manufacturing. The reliability of these simulation tools must be demonstrated in order to give confidence in their results. Standards prescribe a range of techniques for the validation, verification, and calibration of computational electromagnetics solvers including external references based on measurement or for cross-validation with other models. We have developed a modular test-suite based on an enclosure to provide the EMC community with a complex external reference for model validation. We show how the test-suite can be used to validate a range of electromagnetic solvers. The emphasis of the test-suite is on the features of interest for EMC applications, such as apertures and coupling to cables. We have fabricated a hardware implementation of many of the test-cases and measured them in an anechoic chamber over the frequency range to 1–6 GHz to provide a measurement reference for validation over this range. The test-suite has already been used extensively in two major aeronautical research programs and is openly available for use and future development by the community.

Partial Element Equivalent Circuit Models of Three-Dimensional Geometries Including Anisotropic Dielectrics

During recent years anisotropic materials have received an increasing interest and found important applications in the field of shielding and antennas. The anisotropy may be due to intrinsic properties, or as a consequence of mixing. Intentionally or not, the anisotropy impacts the electromagnetic (EM) behavior of a system. Therefore, it is desirable to be able to incorporate the anisotropic effects in an EM model, to allow design tasks and analysis. In this paper, the partial element equivalent circuit (PEEC) formulation is extended to handle nondispersive linear anisotropic dielectrics. The anisotropic dielectric PEEC cell is derived and the resulting PEEC equations are developed into a descriptor system form, which is well suited for implementation in SPICE-like solvers, and for reduction by model-order reduction techniques. A verification of the model is given by a numerical example of a patch antenna situated on an anisotropic substrate and the results are in good agreement with a finite-difference time-domain implementation. The proposed PEEC model is of interest for further work, i.e., in the modeling of setups involving mixtures of materials, with an orientational alignment, and engineered materials, encountered in different EM compatibility applications.

Patch Antenna Miniaturization Using CSRR

A novel metamaterial structure has been proposed for Electromagnetic Compatibility (EMC) applications. A patch antenna with dimension of 18 mm × 13.9 mm and resonating at 5 GHz has been designed and the effect of Double Negative (DNG) metamaterial loading for the patch size reduction as well as a lowering in resonance frequency for the fixed size patch antenna has been proposed. A size reduction of 72.5% in the patch antenna has been obtained with the loading of this metamaterial structure and the effect of loading the metamaterial shows that without reducing the size, the patch antenna can work at 3.7 GHz resonance, providing a lowering in resonance frequency by 26%. The metamaterial structure consists of two concentric loops with an outer radius of 3.1 mm. The width of the ring is 1.0 mm and the split is 0.5 mm and has been designed over a 1.57 mm thick Fr4 substrate. The bending effect of the patch antenna with and without metamaterial loading and its comparison with the planar patch antenna has been also shown here. The metamaterial structure has shown its resonance at 5 GHz and its permittivity and permeability behavior over the desired frequency range has been plotted. The simulation of traditional patch antenna and patch antenna over metamaterial has been compared for its return loss, VSWR, gain and efficiency. Finally, a spice circuit for the S parameter of the metamaterial, patch antenna and patch antenna loaded with metamaterial has been obtained using Matlab and ADS for its equivalence to 3D field solver and its comparison has been plotted for its verification.

Electromagnetic and thermal properties of three-dimensional printed multilayered nano-carbon/poly(lactic) acid structures

A new type of light-weight material produced by 3D printing consisting of nano-carbon doped polymer layer followed by a dielectric polymer layer is proposed. We performed temperature dependent characterization and measured the electromagnetic (EM) response of the samples in the GHz and THz range. The temperature dependent structural characteristics, crystallization, and melting were observed to be strongly affected by the presence and the number of nano-carbon doped layers in the sandwich structure. The electromagnetic measurements show a great potential of such a type of periodic material for electromagnetic compatibility applications in microwave frequency range. Sandwich structures containing only two nano-carbon layers already become not transparent to the microwaves, giving an electromagnetic interference shielding efficiency at the level of 8–15 dB. A sandwich consisting of one nano-carbon doped and one polymer layer is opaque for THz radiation, because of 80% of absorption. These studies serve as a basis for design and realization of specific optimal geometries of meta-surface type with the 3D printing technique, in order to reach a high level of electromagnetic interference shielding performance for real world EM cloaking and EM ecology applications.

The Development of an EM-Field Probing System for Manual Near-Field Scanning

This research was conducted to visualize the frequency-dependent electromagnetic field distribution for electromagnetic compatibility (EMC) applications and the time evolution of the current flow induced by an electrostatic discharge (ESD) on complex-shaped electronic systems. These objectives were achieved by combining magnetic field probing with a system that automatically records the probe's position and orientation. The local magnetic field associated with the probe location was recorded and displayed at near real time on the captured 3-D geometry. Consequently, a field strength map was obtained for EMC applications. Also, a video showing the spreading of the ESD-induced current with subnanosecond resolution was captured for ESD applications after the ESD-induced surface current density associated with the probe location was recorded.

A curvilinear stochastic-FDTD algorithm for 3-D EMC problems with media uncertainties

Purpose – Stochastic uncertainties in material parameters have a significant impact on the analysis of real-world electromagnetic compatibility (EMC) problems. Conventional approaches via the Monte-Carlo scheme attempt to provide viable solutions, yet at the expense of prohibitively elongated simulations and system overhead, due to the large amount of statistical implementations. The purpose of this paper is to introduce a 3-D stochastic finite-difference time-domain (S-FDTD) technique for the accurate modelling of generalised EMC applications with highly random media properties, while concurrently offering fast and economical single-run realisations. Design/methodology/approach – The proposed method establishes the concept of covariant/contravariant metrics for robust tessellations of arbitrarily curved structures and derives the mean value and standard deviation of the generated fields in a single-run. Also, the critical case of geometrical and physical uncertainties is handled via an optimal parameteri...

A Novel 2–18-GHz Double-Ridged Horn Antenna with an Improved Feed Section Design

In this article, a 2–18-GHz double-ridged horn antenna is designed, and the effects of the E-plane sidewalls on antenna performance are examined. The modifications implemented in the shape of the ridges cause a better voltage standing wave ratio over the whole frequency band. The double-ridged horn antenna is designed to have fewer parts that reduce the possibility of performance reduction due to the production process. The antenna is modeled using commercial 3D electromagnetic simulation software, CST Microwave Studio (Computer Simulation Technology, Germany). After the simulations, a prototype of the designed model is manufactured and tested. The measurement results are in good agreement with the simulation results. The results show that the antenna has low side-lobe levels with a voltage standing wave ratio less than 1.85 (typically 1.5) over the entire frequency band. The method outlined in this article can be used to design a double-ridged horn antenna as a test antenna in electromagnetic compatibility (EMC) applications.

Coaxial Waveguide Methods for Shielding Effectiveness Measurement of Planar Materials Up to 18 GHz

The issue concerning the measurement of the shielding effectiveness (SE) of planar materials over a wide frequency range is of crucial relevance in several electromagnetic compatibility applications. This paper describes three different coaxial specimen holders for the measurement of the SE of thin metallic films over a nonconducting substrate or sandwiched between two insulating layers from a few kHz up to 18 GHz. Besides the well-known ASTM D4935 flanged coaxial cell, two novel versions of coaxial fixtures with an interrupted and continuous inner conductor are presented and compared. Their limits of applicability, advantages, and drawbacks are discussed with respect to frequency, sample characteristics, and test procedure. The analysis is performed by the use of simple equivalent circuit models, experimentally validated measuring thin copper films of different thicknesses which are deposited on kapton substrates by magnetron sputtering. It is demonstrated that the use of the three methods, properly combined, provides reliable SE results in the overall considered frequency range. It is also shown that the measurement of conducting films between two dielectric layers is critical at frequencies lower than some tens of MHz.

A Family of Ultra-Thin, Octagonal Shaped Microwave Absorbers for EMC Applications

The purpose of this paper is to present efficient models of new octagonal split ring resonant (O-SRR) periodic structures that can offer practical applications for electromagnetic compatibility (EMC) engineers in the area of absorbing materials. The model of an ultra-thin, compact O-SRR absorber for operation at microwave frequencies is introduced, exhibiting very high absorptive regions. The idea is extended to multi-band performance, where two different setups are demonstrated and analyzed. The physics behind the absorption mechanism for the multi-band structures is explained through the surface mechanism.

On Different Approaches to Combine Cable Information Into Near-Field Data for Radiated-Field Estimation

Near-field scanning is often used to solve electromagnetic compatibility (EMC) problems. Aside from the purpose of visualization of near fields, measured near-field data can be used to estimate radiated fields. One of many challenges associated with using near-field to far-field transform technique for EMC application is the handling of attached cables. The objective of this investigation is to evaluate different methods to add cable information to the near-field data for radiated-field estimation. The investigation is carried out using numerical experiments in EMCoS EMC Studio, which is a commercial software tool for EM simulation providing method-of-moments solver. Measurement results from a specially designed test structure are presented to validate the simulation results.

Nonlinear interaction of meta-atoms through optical coupling

We propose and experimentally demonstrate a multi-frequency nonlinear coupling mechanism between split-ring resonators. We engineer the coupling between two microwave resonators through optical interaction, whilst suppressing the direct electromagnetic coupling. This allows for a power-dependent interaction between the otherwise independent resonators, opening interesting opportunities to address applications in signal processing, filtering, directional coupling, and electromagnetic compatibility.

FULLY TIME-DOMAIN SCANNING OF EM NEAR-FIELD RADIATED BY RF CIRCUITS

This paper deals with planar scanning technique of electromagnetic (EM) near-fleld (NF) emitted by electronic printed circuit boards (PCBs) fully in the time-domain (TD). The proposed EM scanning metrology is essentially based on the NF test bench available at the IRSEEM laboratory. It comprises motorized mechanical structures for moving the probe interconnected to electronic measurement instruments and controlled by a driver PC. The synoptic of the test bench is presented and technically examined. The characteristics of difierent elements constituting the measurement chain of the TD test bench understudy are described. The NF metrology developed is originally focused on the measurement of time-dependent magnetic fleld H(t) dedicated to the radiated emission electromagnetic compatibility (EMC) applications. An innovative calibration technique of the loop probe for detecting H(t) is established in order to ensure the post processing and extraction of the measured NF data. Then, validations were carried out via comparison with difierent simulations run with standard commercial tools. Mathematical analyses were also conducted for the improvement of the measurement post processing. To realize the mapping of time-dependent EM fleld components, a software interface edited with the graphical language LabVIEW was emulated to synchronize the probe displacement and the data acquisition. An UWB amplifler with average gain about 30dB from DC to 300MHz was designed and fabricated in order to decrease the measurement noise and to improve the quality of measured signals. As results of the study, TD NF mapping is demonstrated successfully by measuring the EM radiation emitted by electronic planar circuits. The technique developed is extremely useful in the fleld of EMC engineering for predicting the transient perturbations susceptible to degrade electronic functions in complex systems encountered usually for the automotive and aeronautic applications.

Experimental Validations of a Simple PCB Interconnect Model for High-Rate Signal Integrity

This paper is devoted to investigating experimental validations of a simple modeling method of PCB interconnects for high-speed signal integrity and electromagnetic compatibility applications. Based on the theoretical approach using the extraction method of the interconnect per-unit-length RLCG parameters, the reduced models of the corresponding transfer function, -parameters, and access and transfer impedances are also established. The methodology describing the different steps of the technique proposed for practical use cases in ultra wideband is established. To verify the effectiveness of the concept under consideration, time-domain validations from the frequency-measured data are realized by using printed circuit board microstrip interconnect lines with micrometers width and millimeters long. Therefore, the model was first validated experimentally, and with electromagnetic simulations, in frequency domain via comparison of -parameters and -matrix from dc to some gigahertz. It was found that relative errors lower than 1 dB were evaluated between the insertion loss of the models, simulations, and measurements. Then, by injecting noisy digital- and mixed-signals with 1 Gigasymbol/s, relative errors of lower than 1% were evaluated by considering the time-domain responses. Compared to the existing interconnect modeling tools, the developed one presents a high accuracy, simplicity, and very less computation time.

Statistics for management of complexity in electromagnetism

Electromagnetic Fields (EMFs) have been studied and used for a long time. The past decades have seen a tremendous increase of applications of EMF in daily life. A particularly prevalent application is formed by wireless personal communication devices, e.g., mobile phones with currently more than five billion users worldwide. Large efforts have been expended to develop tools and methods that can be used to design EMF systems, to manage their performance, capabilities, quality, efficiency, compatibility, as well as to ensure that they comply with safety standards. Taking advantage of improvements in computer performance, efficient numerical methods continue to be developed that are being used to predict or characterize the EMF. In addition, particularly significant advances in software implementation and in experimental setups and techniques have been achieved during the past 15 years. Today, computers are capable of handling physically and electrically large problems, almost without limitations, thanks to distributed computing. Numerical methods such as FDTD (Finite-Difference Time-Domain) have been improved and adapted to allow for accurate estimation of EMFs in complex structures. On the experimental side, reverberation chambers have been studied and appear to be well suited to study various applications in electromagnetic compatibility and beyond. Most, if not all, numerical and experimental methods and simulation tools have been designed mainly with a view to solve deterministic problems. In a mathematical framework, these can be defined as well-posed problems, characterized by differential equations for single-mode systems furnished with a complete set of fixed initial and boundary conditions. However, increasingly complex systems need to be handled and solved nowadays, in which one or more of the system parameters or boundary conditions may be ill-defined, i.e., be either unknown or fluctuating in a quasi-random manner, particularly for multi-mode dynamic systems. In addition to an estimate for the solution, a quantitative evaluation and statement of the associated uncertainty in the knowledge of the field quantity of interest is then called for. Computers that are capable of solving deterministic problems with millions of unknowns can provide only approximate solutions to a real physical process, but they cannot handle complex real-life scenarios involving uncertainty. On the other hand, in a physical experiment, the process output can be observed when the input is varying due to uncertainties. In other words, the uncertainties of the system's input parameters “drive” those in the output field variables. Therefore, new approaches to numerical simulation are called for. Worldwide efforts are currently carried out in numerical as well as in experimental approaches in an effort to manage this situation through fusion of experimental, analytical, and statistical–physical methods of characterization. For example, geostatistics are being used to estimate J. Wiart (*) WHIST Lab, Orange Lab, 38 40 rue du General Leclerc, 92794 Issy les Moulineaux Cedex, France e-mail: joe.wiart@orange-ftgroup.com

Study of high-frequency electromagnetic transients radiated by electric dipoles in near-field

The study investigates transient electromagnetic (EM) radiation in the near-field zone of a system of electric dipoles and the usage of the plane wave spectrum (PWS) concept for extraction of a 3-D field from 2-D measurements. Both aspects are important in the modelling and characterisation of radiated emissions in electromagnetic compatibility applications, which are extended here to time domain. Analytical expressions for a set of dipoles excited by short-duration Gaussian pulses, which in the author's approach are used to model EM radiation, are presented and implemented into a Matlab program to calculate the time-dependent distributions of the three electric field components Ex(t), Ey(t), Ez(t). These results are then used to verify the new technique of extraction of the time-domain component Ez(t) of the electric field from measurements of the two other components, Ex(t) and Ey(t). The details of the technique, based on PWS method applied to the time domain, are presented. Very good agreement between the extracted and analytically calculated fields has been achieved. Further verification and comparison has been done by the simulation in the time domain of the system of dipoles using commercial 3-D EM software.

Use of High-Impedance Surfaces in Electromagnetic Compatibility Applications

This paper presents the results of an investigation into numerical simulation tools for high-impedance surfaces (HIS), with the primary aim of assisting in the design and optimization of these structures in electromagnetic compatibility (EMC) applications. The mathematically simple stub technique was used for capacitors and inductances to model lumped L and C in transmission line configurations. The basic principles of the transmission line modeling (TLM) method, such as the equivalences between the field quantities and circuit parameters, are briefly discussed and are applied on a uniform and a high-impedance transmission lines.

TIME DOMAIN PHYSICAL OPTICS FOR THE HIGHER-ORDER FDTD MODELING IN ELECTROMAGNETIC SCATTERING FROM 3-D COMPLEX AND COMBINED MULTIPLE MATERIALS OBJECTS

This paper proposes a hybrid methodology that combines an extended form of Finite-Deference Time-Domain (FDTD) method with Time Domain Physical Optics (TDPO) for analysis of 3- D scattering of combinative objects in complex electromagnetic compatibility (EMC) problems. Establishing a covariant formulation for FDTD, the extended algorithm introduces a parametric topology of accurate nonstandard schemes for the non-orthogonal div-curl problem and the suppression of lattice dispersion. For complex-combined objects including a small size (SS) and large size (LS) parts, using TDPO is an appropriate approach for coupling between two regions. Thus, our technique solves the EMC complexity with the help of higher order FDTD (HOFDTD) and the combinatory structures by using the TDPO. Numerical validation conflrms the superiority of the proposed algorithm via realistic EMC applications.

Performance of thin-film ferroelectric capacitors for EMC decoupling

This paper studied the effects of thin-film ferroelectrics as decoupling capacitors for electromagnetic compatibility applications. The impedance and insertion loss of PZT capacitors were measured and compared with the results from commercial off-the-shelf capacitors. An equivalent circuit model was extracted from the experimental results, and a considerable series resistance was found to exist in ferroelectric capacitors. This resistance gives rise to the observed performance difference around series resonance between ferroelectric PZT capacitors and normal capacitors. Measurements on paraelectric (Ba,Sr)TiO(3)-based integrated varactors do not show this significant resistance. Some analyses were made to investigate the mechanisms, and it was found that it can be due to the hysteresis in the ferroelectric thin films.

Double-Ridged Conical Horn Antenna for 2-18 GHz

In this article, the design and simulation of a conical double-ridged horn (DRH) antenna with high gain and low cross polarization for electromagnetic compatibility (EMC) applications are presented. Broadband pyramidal DRH antennas have been investigated in many references. The distortion of the radiation patterns at higher frequencies is the significant disadvantage of the conventional broadband pyramidal DRH antenna, and the proposed antenna improves the radiation pattern characteristics. The designed antenna has a voltage standing wave ratio (VSWR) less than 2 for the frequency range of 2–18 GHz. Moreover, the proposed antenna exhibits extremely low cross polarization, low side lobe level, very high gain, and satisfactory far-field radiation characteristics in the entire operating bandwidth. A new technique for synthesizing the horn flare section is introduced. A coaxial line to the circular double-ridged waveguide transition is introduced for coaxial feeding of the designed antenna. The proposed antenna is simulated with commercially available packages, such as CST microwave studio (Sax Software Corp.) and Ansoft HFSS (Ansoft Corp.), in the operating frequency range. Simulation results for the VSWR, radiation patterns, and gain of the designed antenna over the frequency band 2–18 GHz are presented and discussed.