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This paper deals with the mitigation of magnetic field levels produced by a wireless power transfer (WPT) system to recharge the battery of an electric vehicle (EV). In this work, an array of active coils surrounding the WPT coils is proposed as a mitigation technique. The theory and new methodological aspects are the focus of the paper. Magnetic field levels in the environment are calculated numerically without and with the presence of an array of active coils in a stationary WPT system for automotive applications. By the proposed mitigation method, the field levels beside the vehicle are significantly reduced and comply with the reference levels (RLs) of the ICNIRP 2010 guidelines for human exposure to electromagnetic fields and the magnetic flux density limits proposed by ISO 14117 for electromagnetic interference (EMI) in cardiac implantable electronic devices (CIEDs). [ABSTRACT FROM AUTHOR]

Electric vehicles (EV) are now considered the present and future of road transportation to reduce the emission of CO2 into the environment and thus progressively reduce global warming and climate change. However, EVs currently have some weaknesses such as the available range of battery-powered EVs and the recharging time of the batteries. To overcome these problems, some electrification projects have been proposed for road transportation such as the dynamic wireless power transfer (DWPT), where an EV charges as it moves along an electrified lane using magneto-resonant coupling between short tracks mounted on the road pavement and the vehicle's onboard pickup coils. While the results are encouraging from an electrical point of view, there is concern regarding the magnetic field in the environment produced by the DWPT coils, which can produce adverse health effects in humans and electromagnetic interference (EMI) in electronic devices. The latter also includes implantable medical devices (IMDs) and in particular cardiac implantable electronic devices (CIEDs), which may be present among vehicle passengers and pedestrians in areas surrounding the vehicle. The aim of this study is the numerical analysis of the EMI produced by a DWPT system in CIEDs with leads such as pacemakers, implantable cardioverter defibrillators (ICDs), etc. EMI is mainly produced by the incident magnetic field and the induced voltage at the input port of a CIED; therefore, in this work the magnetic field levels produced by a DWPT system operating at 85 kHz are calculated first, then the voltage at the input port of a pacemaker is evaluated as that produced by the magnetic field incident on the loop surface formed by a lead implanted in the venous system. According to ISO 14117 standard, it is assumed that the lead loop is planar, semicircular in shape and with an area equal to 225 cm2. Since the lead can be placed anywhere where a human can be and with any orientation, an innovative and sophisticated roto-translation algorithm is proposed to find the maximum value of the peak-to-peak induced loop voltage in the most critical regions inside the vehicle cabin and beside the vehicle near the DWPT coils. The preliminary results obtained show that there is no EMI risk inside the vehicle for the passengers with CIEDs, while some concern for pedestrians is due to the induced voltage at the input port of a CIED with unipolar leads which can exceed the ISO 14117 limit in the region next to the vehicle. [ABSTRACT FROM AUTHOR]

This study focuses on using wireless power transfer (WPT) technology based on magnetic resonant coupling (MRC) to supply electric power to an endoscopic capsule to be used for the direct feeding of specific functions or for battery charging. One of the main limitations of the diffusion of endoscopic capsules is the limited autonomy of the internal battery. The aim of the paper is to present an innovative system to wirelessly power capsules using inductive coupling. Here, a new transmitting coil architecture is proposed to allow the wireless charging of the capsule equipped with a monoaxial receiving coil for any possible geometric position and orientation. The new wearable transmitting coil consists of four rectangular coils with independent excitations, and it is capable of producing a magnetic field in any direction. The obtained results in terms of electrical performance of the proposed WPT system and in terms of in situ electromagnetic physical quantities are compared with the basic restrictions of electromagnetic field (EMF) safety guidelines. The results obtained are very promising, as the proposed WPT configuration can transfer at least 250 mW in a capsule that travels along the entire gastrointestinal tract. [ABSTRACT FROM AUTHOR]

The coexistence issue between ultra-wideband (UWB) radio communication systems and narrow-band wireless LAN systems is investigated by experiments and simulations. The work is divided in two parts. In this Part II, either impulse radio or multiband orthogonal frequency-division multiplex systems are assumed to be the disturbance source, while narrow-band wireless systems based on IEEE 802.11a/b are assumed to be the victims. The electromagnetic interference produced by a UWB disturbance source to the WiFi victim systems is experimentally evaluated by radiated measurements in a semianechoic chamber. Then, an innovative conducted coupling test is proposed to simplify the measurements while maintaining satisfactory accuracy. A simulation method is also proposed to help designers of wireless communication systems. The bit error ratio and packet error ratio are measured to evaluate the level of interference between different radio systems. Some tests are carried out for typical operational conditions of radio systems. Index Terms--Coexistence between wireless systems, conducted test, electromagnetic compatibility (EMC) measurements, interferences of digital radio systems, time-domain measurements, ultra-wideband (UWB) radio characterization.

The correct modeling and measurement of ultrawideband (UWB) radio signal are a critical issue to evaluate the electromagnetic (EM) emission of any communication system based on this technology. In this paper (Part I), UWB radio communication systems based on impulse radio (IR) and multiband orthogonal frequency division multiplex (MB-OFDM) technologies are characterized by simulations and experiments in both frequency and time domains. The EM characteristics of UWB radio are measured by different methods (conducted and radiative) and in different environments (anechoic and reverberation chambers). Index Terms--coexistence between wireless systems, electromagnetic compatibility (EMC) measurements, time-domain (TD) measurements, ultra-wideband (UWB) devices.

A numerical study is proposed to investigate the effects of different RF sources on the specific absorption rate (SAR) and maximum temperature increase in the human eye at different frequencies. In particular, a new model of the human head is presented and compared with an anatomical model of the visible human. The high resolution (0.5 mm) of the proposed model allows to consider more eye tissues than previous studies distinguishing the sclera from the retina and choroid. New values of blood perfusion and metabolic rate of these tissues are derived. A plane-wave field is considered as far-field exposure, while realistic models of mobile phone and dipole antennas are used as primary sources for near-field exposure. The obtained results show that the distributions of the SAR and temperature increase depend on the frequency, position, and kind of sources. Finally, attention is paid to the maximum temperature increase in the lens for the SAR values prescribed by the Commission on Non-Ionizing Radiation Protection. To this aim, a scaling approach is proposed, and significant values of temperature increase are found (about 0.3 [degrees]C for general public exposure and about 1.5 [degrees]C for occupational exposure) for the most critical cases of near-field exposures. Index Terms--Cellular phones, finite difference method, human exposure to electromagnetic fields (EMF), human eye modeling, numerical dosimetry, thermal simulation.

An experimental procedure to detect and localize defects in shielded cables is presented. First, time-domain measurements are carried out by injecting a short rise time pulse in the input section of the shielded cable. Then, the clean algorithm is applied to the measurement results to identify possible damages in the cable line. The localization of the cable section with defects is finally obtained in a very simple way due to the adopted method of measurement in time domain using a ultrawide-band pulser with a very fast rise time. The proposed method is validated by detecting and localizing known defects purposely introduced in test cables. Index Terms--Clean algorithm (CA), defect localization in cables, shielded cable, time-domain (TD) measurement, time-domain reflectometry (TDR), ultrawide-band (UWB) signal.

A numerical method is proposed to model transients in a shielded cable embedded in a three-dimensional field domain by using the finite-difference time-domain (FDTD) method. The coaxial shielded cable is assumed to be a multiconductor transmission line (MTL). The in cell voltage and the current on the external shield surface are calculated by a full-wave method, while the core current and the core-to-shield voltage are analyzed by assuming the validity of the quasi-TEM propagation mode inside the shield. The internal and external shield surfaces are coupled by the transfer admittance and by the transfer impedance of the cable shield. The solution is obtained by the FDTD method combining the MTL equations with the field equations. The proposed time-domain method takes into account the frequency-dependent parameters of the cable conductors by recursive convolution techniques. The validation of the procedure is performed in simple test configurations. Index Terms--Electromagnetic compatibility/interference (EMC/EMI), finite-difference time-domain (FDTD) method, multiconductor transmission lines (MTL), shielded cables.

An original finite-element approach is presented to calculate the capacitance matrix of a uniform multiconductor wire line. The examined two-dimensional (2-D) domain is discretized by nodal-based triangular elements where the Laplace equation is solved. A new procedure is developed to take into account the presence of the wires, which are assumed to be located in the vertex nodes of the FEM mesh. Through the proposed procedure, the physical dimensions of the wire cross sections are considered modifying the terms of the local stiffness matrix in the finite elements surrounding the wires. A further modification of the local FEM matrices allows to consider the logarithmic variation of the electrical potential around the wires. The procedure is efficient from a numerical point of view since it avoids the fine discretization of the nonconductive region surrounding the wire while achieving a good numerical accuracy. Numerical examples are given and compared with the analytical solutions for canonical configurations, including wires with dielectric cover. Index Terms - Electrostatics, FEM, MTL, per-unit-length parameters.

An uninterruptable wireless power supply is developed for a left ventricular assist device (LVAD), which is an implanted, electrically driven centrifugal pump used to treat advanced heart failure pathologies. The LVADs are currently powered through a cable driveline (DL) that exits the patient's body through the skin. Here, an innovative uninterruptable power supply is presented, based on a hybrid wireless/wired architecture: the electric power of 10 W is transferred by the near field wireless power transfer technology operating at 300 kHz, from outside the human body to an implanted subcutaneous receiver, and then by an internal cable to the LVAD. A significant improvement of the subcutaneous receiver is here proposed, based on the integration in the receiving coil of a battery pack providing the following benefits: no-break power supply for the LVAD; peak load management; enhanced system reliability; elimination of DL infection; enhancement of patient's quality of life. The proposed system is first designed and optimized, then a demonstrator is made and tested in a laboratory using the latest LVAD generation. The measured coil currents are used as sources for dosimetric analysis to assess the compliance of the system with the electromagnetic field safety and thermal regulations. [ABSTRACT FROM AUTHOR]

This article deals with an innovative wireless charging system for an implanted capsule robot. The transmitting coil is given by a combination of a Helmholtz coil and a birdcage coil. This coil configuration generates a magnetic field with all nonzero field components for any location within the human torso. Therefore, a single axis receiving coil wound around a cylindrical shaped ferrite core is able to receive a significant quantity of electrical energy for any capsule orientation and position. Design guidelines are provided and illustrative examples are given. Assuming a capsule of 2 cm length and 1 cm diameter we can transfer at least 1 W to the load with a minimum power transfer efficiency larger than 10% without considering electronic losses. Finally, compliance with electromagnetic field safety limits is assessed by a numerical dosimetric analysis. [ABSTRACT FROM AUTHOR]

This paper describes a new procedure for the numerical computation of the electric field and current density distributions in a dc electrostatic precipitator in the presence of dust, taking into account the particle-size distribution. Poisson's and continuity equations are numerically solved by supposing that the coronating conductors satisfy Kaptzov's assumption on the emitter surfaces. Two iterative numerical procedures, both based on the finite element method (FEM), are implemented for evaluating, respectively, the unknown ionic charge density and the particle charge density distributions. The V-I characteristic and the precipitation efficiencies for the individual particle-size classes, calculated with reference to the pilot precipitator installed by ENEL (Italian Electricity Board) at its Marghera (Venice) coal-fired power station, are found to be very close to those measured experimentally.

Analytical solution of lossless field-excited multiconductor transmission lines is presented. The equivalent circuit of a multiconductor transmission line with distributed sources is reduced to a simple lumped parameter circuit with independent voltage sources at both the ends of the transmission line. The transient source waveforms are analytically estimated for exponential time dependence of the external field, as EMP, ESD, and lightning. The method is suitable for a direct implementation in computer-aided circuit analysis codes and enables a very fast analysis for any load condition. Some numerical results are presented for single conductor and multiconductor lines excited by an EMP plane-wave field.

This article deals with the electromagnetic interference (EMI) in a cardiac implantable electronic device (e.g., implantable cardioverter-defibrillator or cardiac resynchronization therapy) generated by a left ventricular assisted device (LVAD) powered by a wireless power transfer (WPT) system. Wireless LVAD, not yet available in the market, is currently being investigated for many aspects spanning from electronics, hydraulic, electrical feeding, mechanical, and its possible impact on other implanted devices, such as a cardiac implantable electronic device (CIED). No results are yet published on possible EMI effects produced by the WPT coil currents in the pacing leads of a CIED implanted in the same patient with the LVAD. To this aim, the next generation of wireless LVADs with transcutaneous WPT system is first described, and, then, used to predict the induced voltage by the WPT system on a CIED lead. The obtained results demonstrate as the proposed WPT system, tested in accordance with the ISO 14117 standard, does not interfere with other CIEDs. [ABSTRACT FROM AUTHOR]

A novel design of active coil shielding is proposed to reduce the magnetic field generated by the currents flowing into the coils of a wireless power transfer (WPT) system for charging the batteries of an electric vehicle (EV). The main idea is to divide the traditional active loop used to shield a source in two separate shielding coils so as not to adversely affect the WPT performance. This concept is applied to shield the WPT coils, and, therefore, in the proposed design, there are active coils placed on the ground parallel to the primary coil of the WPT and some others on board below the vehicle, planarly located with the secondary coil. The currents on the active coils are optimized in order to minimize the magnetic field in the most critical zone accessible from humans, i.e., region besides the EV and in the cabin. [ABSTRACT FROM AUTHOR]

The artificial material single-layer (AMSL) method, recently proposed to model solid conductive shields in finite-element solvers without using a fine discretization, is here extended to model multilayer shields. First, the admittance matrix of a multilayer shield is analytically derived by the transmission line (TL) theory. Then, considering that the field through conductive shields propagates normally to the shield surface, the TL admittance matrix is equated to that of a 1-D finite element to extract the physical constants of a homogenized artificial material. These constants are adopted to model the multilayer shield region in the finite-element method (FEM) calculations by using only one layer of finite elements in the direction of the field propagation. By the AMSL-FEM, the field propagation through the multilayer shield is accurately modeled taking into account the skin effect and avoiding the fine discretization of the shield. [ABSTRACT FROM AUTHOR]

The shielding technique by active coils is proposed to mitigate the magnetic field produced by a wireless power transfer (WPT) system based on near field coupling. General guidelines are provided for the active shielding design to shield the source for emission reduction or to shield the victim for immunity enhancement. Then, a method is proposed to identify the suitable excitation of the active coils. The proposed method permits the mitigation of the magnetic field in a specific point or of the induced effects in a loop area. Furthermore, the influence of the active shielding on the performance of a WPT system is also investigated. Finally, the proposed solution for active shielding is validated by measurements. A shielding effectiveness (SE) of about 20 dB on the considered area is obtained with a negligible degradation of the WPT system efficiency. [ABSTRACT FROM AUTHOR]

This paper deals with the assessment of the induced voltage in an unipolar pacing lead produced by the coil currents of a wireless power transfer (WPT) system for battery recharging of an electric vehicle (EV). In the first part of the work, the magnetic field distributions inside and outside an EV equipped with the WPT technology is carried out by finite element (FE) simulations using the artificial material single layer (AMSL) method. The FE-AMSL method efficiently predicts field reflection and the transmission of the EV conductive bodyshell, while avoiding the fine mesh discretization of the conductive regions and taking into account the skin effect. In the second part, the calculated magnetic field is used as an electromagnetic source of a unipolar pacing lead implanted in the human body. Some original calculation methods are proposed to assess the induced voltage in the loop area formed by a lead. By the proposed procedure, it is possible to quickly calculate the electromagnetic interference in the pacemaker during wireless battery recharging of an EV. The induced voltage is one of the most important parameters to perform the risk analysis and assessment. [ABSTRACT FROM AUTHOR]

Impedance network boundary conditions (INBC's) are implemented in the finite-difference time-domain (FDTD) method to analyze the electromagnetic field around penetrable shield structures. The shield region is eliminated from the computational domain and the INBC's are applied on the new boundary surfaces, i.e., shield surfaces, to take into account the field discontinuity produced by the shield. The INBC's represent an important extension of the well-known surface impedance boundary conditions (SIBC's) since the INBC's model accurately the coupling of the electromagnetic fields through penetrable shields and lead to a significant reduction of the number of the FDTD unknowns. The INBC expressions are given analytically in both frequency and time domains, and the INBC implementation in a FDTD code is discussed. The proposed INBC-FDTD method is numerically efficient because the resulting convolution integrals are recursively solved. Furthermore, approximate time-constant INBC's are proposed which are valid for many practical applications. The analysis of transient electromagnetic fields around penetrable conductive shields in simple test configurations are presented and compared with the analytical solutions. Index Terms--EMC, FDTD method, impedance network boundary conditions (INBC's), recursive convolution techniques, shielding, surface impedance boundary conditions (SIBC's).

This paper deals with the extension of the artificial material single-layer (AMSL) method, recently developed to model electromagnetically a thin conductive material using the finite-element method (FEM), to the more general case of transversally anisotropic shields. The analogy between the field equations and the multiconductor transmission line (MTL) equations is here used to calculate the admittance matrix of a thin anisotropic material. This admittance matrix is then imposed to be that of an equivalent circuit with lumped parameters. Thus, it is possible to synthetize the AMSL tensors containing the specific constants to be used in commercial software tools. The adoption of the AMSL method in FEM simulations avoids a fine discretization inside the thin conductive anisotropic material required at high frequency. Simple tests are finally carried out to validate the proposed method. [ABSTRACT FROM AUTHOR]

In this study, the electric field induced inside two realistic anatomical models placed near or inside an electric vehicle made of carbon-fiber composite while charging its battery with a wireless power transfer (WPT) system has been investigated. The WPT source consists of two parallel inductive coils operating with a power output of 7.7 kW at two different frequencies of 85 and 150 kHz. Since a misalignment between the primary and the secondary coil creates higher induced fields, a misalignment of 20 cm is also considered as the worst-case exposure condition. The analysis of the obtained results shows that the International Commission on Non-Ionizing Radiation Protection (ICNIRP) basic restrictions are exceeded by 1.3 dB and 4.8 dB for the aligned and misaligned coil positions, respectively. This exceedance is however confined only in a small area of the driver's foot. [ABSTRACT FROM AUTHOR]

This study deals with the design and the optimization of a wireless power transfer (WPT) charging system based on magnetic resonant coupling applied to an electric vertical take-off and landing Unmanned Aerial Vehicle (UAV). In this study, a procedure for primary and secondary coil design is proposed. The primary circuit in the ground station consists of an array of coils in order to mitigate the negative effects on the coupling factor produced by the possible misalignment between the coils due to an imperfect landing. Key aspects for the design of the secondary coil onboard the UAV are the lightness and compactness of the WPT system components. A demonstrative prototype of the WPT system is applied to a commercial drone. The WPT electrical performances are calculated and measured. Finally, an automatic battery recharge station is built where the drone can autonomously land, recharge the battery and take off to continue its flight mission. [ABSTRACT FROM AUTHOR]

A new artificial material single layer (AMSL) model is presented to solve shielding problem. The field penetration through the conductive shield is described by lossy transmission line equations. The resulting equations are used to numerically synthetize an equivalent material for the shield region having the same geometrical configuration of the original shield, but different specific constants. The AMSL method is very accurate and highly efficient since it allows to discretizing the shield region using only a single layer of finite elements avoiding the fine discretization required by the finite-element method (FEM) to model the skin effect. The most relevant aspect of the proposed procedure is that the AMSL method can be easily implemented in FEM-based commercial software tools. [ABSTRACT FROM AUTHOR]

The configuration of an infinite planar conductive shield is examined when it is excited by an electromagnetic near field generated by a coil current source as that of a wireless power transfer (WPT) system. The analytical expressions of the electromagnetic field based on the transmission theory of shielding are given for different frequencies and different incidence angles of the near field generated by the coil current, assuming the conductive planar shield placed in the close proximity of the coil. The obtained results are discussed and compared with other traditional analytical and numerical solutions. [ABSTRACT FROM AUTHOR]

This paper deals with wireless power transfer technology applied to charge the battery of a short-distance electric vehicle. Different compensation topologies (series–series and LCC compensations) are examined and compared in terms of magnetic field emission and system efficiency. The investigation is carried out by simulations and measurements taking into account the variation of the coupling factor due to possible lateral misalignment of the parallel coils, and of the load conditions that depend on the level of the battery charge. [ABSTRACT FROM PUBLISHER]

In this study, the inter- and intralaboratory comparison of coupling factors is discussed for human exposure to nonuniform magnetic field from different wireless power transfer (WPT) systems. In order to derive the coupling factors, different laboratories computed the internal electric field and specific absorption rate (SAR) for different WPT configurations. The concept of coupling factors was originally introduced in the International Electrotechnical Commission (IEC) 62311 and 62233 standards, for product safety assessment. For WPT systems, extension of the coupling factors is discussed in the IEC working group. This factor enables the estimation of the internal electric field and the SAR without detailed computation using human anatomical models. The coupling factors were computed for different WPT systems, such as an electric vehicle charging at approximately 100 kHz, induction coupling systems (140 kHz band), and home appliances (6.78 MHz). Four in-house codes were used in this inter- and intralaboratory comparison study to compute the coupling factors for the systems. Similar tendencies were observed in the coupling factors obtained by the groups. The difference between the coupling factors of different research groups is 30% when considering the same exposure scenarios. The coupling factors for different WPT systems are different because of the frequency, coil size, and existence of the magnetic sheet (shield). The variability of the internal electric field for WPT systems is also investigated to set the coupling factor required for practical use. [ABSTRACT FROM PUBLISHER]

A wireless power transfer (WPT) system based on magnetic resonant coupling is applied to a pacemaker for recharge its battery. The primary coil is assumed to be on-body, while the secondary coil is in-body. Three different configurations of the secondary coil are hereby investigated placing it inside the titanium case of the pacemaker, on the top surface of the case, or being part of the top surface case. The operational frequency is fixed to be at a relatively low frequency (20 kHz) in order to allow field penetration through the case and to limit the electric and magnetic field safety and thermal increase issues. For each examined configuration, these aspects are investigated by numerical and experimental techniques. The obtained results demonstrate the feasibility of the proposed solutions highlighting their advantages and disadvantages. [ABSTRACT FROM PUBLISHER]

Emerging technologies, such as rescue robots, exploiting radio localization and communication systems may become capable of improving the rescue of buried people as a consequence of anthropic or natural disaster, but suitable propagation models in such a scenario are necessary. The earthquake damage experienced in the Italian historic town of L'Aquila turns out to be useful to improve the knowledge of the behavior of radio propagation in areas with collapsed buildings. After the earthquake, a measurement campaign was then carried out in two different locations with different levels of disaster (completely or partially collapsed buildings). Continuous-wave radio transmitters operating at 434 and 868 MHz have been introduced under rubble, and their signals have been measured at different points in the surrounding area. Two-port measurements with a large frequency span have been also performed. The main results are the estimates of the excess path loss and the group delay. [ABSTRACT FROM PUBLISHER]

The applicability of the time-reversal theory by the pseudospectral time-domain method is investigated to localize a medical implant equipped with an ultrawideband radio and embedded in a randomly lossy dielectric medium. A localization algorithm is implemented and tested for various test cases. A comparative analysis with the finite difference time-domain method implementation is performed in terms of memory occupation and computational time. [ABSTRACT FROM PUBLISHER]

This paper deals with the time-domain numerical calculation of electromagnetic fields in media described by linear Drude dispersive models. The frequency-dependent finite-difference time-domain method is applied to solve multipole Drude equations using equivalent circuit models. Two new different circuit methods, named CIRC and PCRC, are proposed. The dispersion analysis and the stability conditions are carried out for these methods. Finally, illustrative examples are provided. [ABSTRACT FROM AUTHOR]

The aim of this study is to predict the electromagnetic interference (EMI) effect produced by a dynamic wireless power transfer (DWPT) system on a buried multiconductor signal cable. The short-track DWPT system architecture is here considered with an operating frequency of 85 kHz and maximum power transferred to an EV equal to 10 kW. The EMI source is the DWPT transmitting coil which is activated when a vehicle passes over it. The electric and magnetic fields in the earth produced by the DWPT coil currents are calculated numerically using the finite elements method (FEM). These fields are then used to derive the voltage and current sources that appear in the field-excited multiconductor transmission line (MTL) model, used for the buried shielded cable. The MTL is analyzed considering the first ten harmonics of the current. The currents and voltages at the terminal ends are calculated considering the wireless charging of a single electric vehicle (EV) first, and then the simultaneous charging of 10 EVs which absorb a total power of 100 kW. The preliminary results reveal possible EMI problems in underground cables. [ABSTRACT FROM AUTHOR]

A circuit-based implementation of the Leontovich impedance boundary condition (IBC) is proposed. The surface impedance of a lossy medium is approximated by a series of first-order rational functions using the vector-fitting technique. Thus, an equivalent analogical circuit with lumped linear time-invariant parameters is derived, which is simply analyzed in time domain without performing any convolution. The implementation of the equivalent circuit in the finite-difference time-domain method is detailed for different circuit configurations. Finally, the advantages of the proposed method are presented and compared with those of other numerical procedures for the solution of the IBC in time domain. [ABSTRACT FROM AUTHOR]

An equivalent circuit is proposed to model frequency selective surfaces (FSSs) made of optically transparent metal patches. The field penetration through a unit cell of a simple FSS is modeled circuitally by a shunt admittance composed by inductance and capacitance, while the losses in the parts covered by metal thin film are modeled by resistances. The circuit results are validated by full-wave numerical simulations for different test configurations. The circuit model permits fast simulations adequate for FSS design. [ABSTRACT FROM PUBLISHER]

This paper deals with contact currents that may occur when the human body is in contact with two electrodes at different electrical potentials, e.g., an electrical/electronic device and the floor. Actually, any device must comply not only with electromagnetic compatibility and safety requirements, but also with specific electromagnetic field exposure recommendations in order to prevent health hazards for the occupational and general public population. Since the contact currents depend on the applied voltage and on the human body impedance, this last parameter has been measured for several configurations in a broadband frequency range, from 40 Hz to 110 MHz. From the measurement results, a new equivalent circuit of the human body impedance is derived by using a vector-fitting procedure. This equivalent circuit is very easy and can be adopted for compliance tests against contact currents. [ABSTRACT FROM AUTHOR]

The paper deals with the numerical prediction of the specific absorption (SA) of ultra wideband (UWB) radio systems for wireless body area network (BAN). The electro-magnetic analysis is performed by a frequency-dependent finite difference time domain (FD²TD) method here proposed with a new formulation based on a total current density approach. A first order Debye approximation is used to model the frequency-dependent properties of the human body in the frequency range of the UWB signals. The proposed method permits to assess the specific absorption and power loss in the human body exposed to an UWB pulsed source. Different numerical models of the human bodies are finally considered in order to investigate safety aspects. [ABSTRACT FROM AUTHOR]

The paper deals with the numerical prediction of the magnetic shielding of a coated aperture in a perfectly conductive planar shield. The single layer or multilayer thin film resistive coating is characterized and homogenized by using the transmission line approach. The electromagnetic analysis is performed by two methods: 1) a lumped circuit approach with numerically calculated parameters; 2) a finite element method (FEM) approach using the impedance network boundary conditions (INBCs). The results obtained by the two methods in some test configurations are validated and discussed. [ABSTRACT FROM AUTHOR]