Francesca Maradei

Time domain analysis of lossy shielded cables by CAD circuit simulators

A time domain procedure is proposed to analyze by CAD circuit simulators the voltage and current wave propagation in shielded cables taking into account frequency-dependent losses. First, the line is discretized in a series-cascade of line sections. Second, each line section is modeled by a two-port network with lumped time-constant parameters obtained by applying the vector fitting technique. The series-cascade circuits are then analyzed by CAD circuit simulators. The obtained results are compared with those obtained by measurements and by the frequency domain solution of the transmission line equations.

Robust LCC compensation in wireless power transfer with variable coupling factor due to coil misalignment

The paper provides an investigation of a possible application of wireless power transfer (WPT) technology to recharge the battery of a short-distance electric vehicle. The performance of the WPT system working at 85 kHz is first investigated by simulations. A robust LCC compensation network suitably tuned is then investigated with the goal to analyze the influence of design parameters on the compensation strategy. Particular attention is addressed to evaluate the deterioration of the WPT system performance due to coil misalignment. Finally, the WPT performances are evaluated demonstrating the feasibility of the proposed WPT technology.

Near-Field Reduction in a Wireless Power Transfer System Using LCC Compensation

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.

Optimum coil configuration of wireless power transfer system in presence of shields

This paper deals with the coil optimization of a wireless power transfer (WPT) system configuration in presence of a shield which is used to mitigate the magnetic field in the environment. The performance of the WPT system and the magnetic field shielding are investigated by simulations and measurements in a WPT demonstrator working at the frequency of automotive applications (f=20-85 kHz). The proposed innovative simulation method allows choosing the optimum shield design of a WPT system in order to assure good electrical performance and compliance with EMC and EMF safety standards.

Assessment of magnetic field levels generated by a wireless power transfer (WPT) system at 20 kHz

An investigation is carried out to assess the magnetic field levels produced by the currents flowing in two magnetically coupled coils in air used for wireless power transfer (WPT). The currents are determined by an equivalent circuit, while the magnetic field in the surrounding environment is numerically and analytically calculated. The simulation procedure is validated by comparison with experiments.

Circuit-Oriented FEM Modeling of Finite Extension Graphene Sheet by Impedance Network Boundary Conditions (INBCs)

The paper deals with an efficient and accurate circuit-oriented model of multilayer graphene sheet in finite-element method (FEM) by impedance network boundary conditions (INBCs). The INBCs have been developed in the past to model efficiently the field penetration through thin conductive shields. Here, INBCs are used to model graphene sheet by an original and simple circuit-oriented FEM model. The efficiency of the method is proven by validation in different test configurations available in litterature. The proposed circuit-oriented FEM model seems to be very suitable to model next generation smart materials using graphene.

Finite-Element Analysis of Temperature Increase in Vascularized Biological Tissues Exposed to RF Sources

A new model of numerical dosimetry is proposed for RF exposure. First, the specific absorption rate (SAR) is computed. Then, the heat transfer governed by the bio-heat equation with convection term is numerically solved by a finite-element method (FEM) procedure considering the discrete vascular model of the perfused tissue. By some manipulations of the FEM equations and by generating an adequate FEM mesh, it is possible to solve the thermal convection in the blood vessels considering a one-dimensional domain embedded in the fully three-dimensional domain where only the thermal diffusion is analyzed.

Prediction of shielding effectiveness in graphene enclosures by FEM-INBC method

The paper provides an investigation on the shielding effectiveness (SE) of graphene planar sheets and enclosures by a numerical tool. The finite element method-impedance network boundary conditions (FEM-INBC) method has been recently used to model planar graphene layers. Here, this method is applied to model complex geometries as two-dimensional enclosures with shaped graphene sheet walls.

Circuit-Oriented Solution of Drude Dispersion Relations by the

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.

{\rm FD}^{2}{\rm TD}

A UHF RFID antenna is proposed for human tracking applications. The antenna size is adequately designed in order to satisfy special requirements: compact antenna size, read range greater than 3 m, respect of UHF RFID emission standards avoiding spurious emission. The antenna design is carried out by co-simulation between electromagnetic fields and circuit solvers.