F. Maradei

Magnetic field computation in a physically large domain with thin metallic shields

A three-dimensional edge element procedure is presented to analyze the magnetic field around thin shields embedded in a physically large domain. The shield region is eliminated from the computational domain and coupled boundary conditions named impedance network boundary conditions are imposed on the new boundary surfaces to take into account the field discontinuity produced by the eliminated shield. An experimental setup is built and the measured magnetic fields are compared to the results obtained by the proposed procedure.

Prediction of voltage and current propagation in twisted wire pairs (TWPs) by a circuit model

The performances of a twisted wire pairs (TWP) cable above ground are analysed in order to predict the internal propagation. To take into account the nonuniformity produced by the twists, the TWP line is discretized into sections of parallel wire transmission line (TL) whose different electrical parameters are derived analysing the different TWP cross-sections by the finite element method (FEM). The different TWP sections are then connected in a series cascade and the resulting configuration is analysed by a CAD circuit simulator. A comparison of the results obtained in the frequency range 40 MHz - 1 GHz by the proposed model with measurements is presented

Fast calculation of dielectric substrate losses in microwave applications by the FD 2 TD method using a new formalism

The paper deals with the electromagnetic characterization of a dielectric substrate by a numerical analysis. The electromagnetic analysis is performed by a frequency-dependent finite difference time domain (FD2TD) method with a new formulation. A multi-pole Debye dispersive relation is used to model frequency-dependent properties of dispersive dielectrics. The proposed method is suitable to predict efficiently substrate dielectric losses in microwave and RF applications.

FD 2TD analysis of electromagnetic field propagation in multipole debye media with and without convolution

This paper deals with the time-domain numerical calculation of electromagnetic (EM) fields in linearly dispersive media described by multipole Debye model. The frequency-dependent finite-difference time-domain (FD2TD) method is applied to solve Debye equations using convolution integrals or by direct integration. Original formulations of FD2TD methods are proposed using different approaches. In the first approach based on the solution of convolution equations, the exponential analytical behavior of the convolution integrand permits an efficient recursive FD2TD solution. In the second approach, derived by circuit theory, the transient equations are directly solved in time domain by the FD2TD method. A comparative analysis of several FD2TD methods in terms of stability, dispersion, computational time and memory is carried out.

Magnetic field levels in drones equipped with Wireless Power Transfer technology

A Wireless Power Transfer (WPT) system based on magnetic resonant coupling is applied to a small electrical Unmanned Aerial Vehicle (UAV) to recharge its battery. The transmitting coil is assumed to be on a terrestrial base station, while the receiving coil is onboard. The operation frequency is fixed to 150 kHz. Key aspects for this kind of application are the reduction of the weight of the onboard WPT system while maintaining high WPT efficiency and avoiding EMC/EMI problems on the drone electronic system. In this study, the feasibility of the WPT charging system applied to a demonstrative drone has been proved.

Induced Effects in a Pacemaker Equipped With a Wireless Power Transfer Charging System

This study deals with the intrasystem electro-magnetic compatibility (EMC) issue produced by a Wireless Power Transfer (WPT) charging system applied to a pacemaker. A co-simulation circuit/field method is proposed to predict the induced voltage at the input port of the pacemaker.

Induced effects in a pacemaker equipped with wireless power transfer charging system

This paper deals with the intrasystem electromagnetic interference (EMI) in a pacemaker equipped with a wireless power transfer (WPT) charging system. The WPT application to pacemakers is very new, and no results are yet published on possible EMI effects produced by the WPT coil currents in the pacemaker pacing leads. To this aim, an efficient and original co-simulation circuit/field method is proposed to predict the induced voltages on a pacing lead. In the numerical calculation, the pacemaker with WPT secondary coil and a pacing lead is implanted in a sophisticated human body model. The numerical results are validated by measurements showing a good agreement. The proposed approach would be a useful tool for pacemaker EMI compliance tests and safety assessment evaluations.

Numerical simulation of blood vascularization influence in microwave ablation

A simulation of tumour ablation in liver tissue is presented. The ablation is produced by a thin coaxial antenna excited at microwave (MW) frequency. The electromagnetic field and the specific absorption rate (SAR) are calculated by the finite element method. Then, the thermal bio-heat equation (BHE) is solved by assuming the SAR as heat source. The presence of blood vessels in the examined domain is investigated by considering the convection-diffusion BHE. Some test cases are finally proposed to evaluate the influence of the blood velocity on the temperature distribution.