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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]

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.