Bélahcène Mazari

Applications of the Near-Field Techniques in EMC Investigations

A completely automatic near-field mapping system has been developed within the Research Institute for Electronic Embedded Systems (IRSEEM) in order to determine the electromagnetic field created by electronic systems and components. This test bench uses a 3-D positioning system of the probe to make accurate measurements. This paper presents some applications of the near-field techniques in EMC investigations. In the first part, near-field measurements are used to locate precisely the electromagnetic sources of a limiter device. In the second part, we present an equivalent model of the radiated emission of an integrated circuit. In the last part, the near-field test bench is used to characterize faults in a cable.

Characterization and Modeling of the Susceptibility of Integrated Circuits to Conducted Electromagnetic Disturbances Up to 1 GHz

This paper deals with the characterization, as well as the modeling, of the susceptibility of integrated circuits (ICs) to conducted electromagnetic disturbances such as a continuous-wave disturbance. Based on accurate measurement results, a robust mathematical model to predict the susceptibility of a CMOS inverter is developed. This model is based on a neural network approach and is validated up to 1 GHz for different test criteria. A good agreement between measurements and simulated results is reported. The mathematical model is implemented in a software tool such as Advanced Design System in order to facilitate its operation in the evaluation of the susceptibility of ICs.

Modeling Magnetic Emissions Combining Image Processing and an Optimization Algorithm

An automated procedure for modeling the radiated emissions of electronic devices is presented in this paper. The principle of the model is to replace the device by a set of electric dipoles defined by their positions, orientations, lengths, and currents. Thus, this modeling procedure aims to determine the number of dipoles and their parameters with a minimum user intervention. The procedure is divided into three parts: the near-field measurements of the tangential components of the magnetic field, an image processing to obtain the number of sources of the model, and the application of an optimization algorithm in order to obtain the different parameters of the model, such as the current and the position of each source.

A Radiated Emission Model Compatible to a Commercial Electromagnetic Simulation Tool

To evaluate magnetic fields radiated by electronic components, different radiated emission models have been created. Within IRSEEM, a model based on equivalent sources obtained from near-field measurements has been developed. The aim of our study is to insert this model into commercial electromagnetic tools such as HFSS to make it helpful for engineers.

Modeling the Electromagnetic Radiation of Passive Microwave Components Using a Near-Field Scanning Method

This paper presents a heuristic optimized model for describing the electric- and magnetic-radiated emissions from passive microwave components. The main idea has been derived from a previously built model at the Research Institute for Embedded Electronic Systems, which models only the radiated magnetic field. The modeling procedure is based on the use of elementary dipoles. The model extraction is a two-step technique: extraction of the initial dipole parameters (namely their orientation and currents) and an optimization. The Levenberg-Marquardt algorithm is used in order to optimize the dipole parameters, keeping in mind their physical sense. The tangential components of the measured magnetic field are used to build the model.

Near-field techniques for detecting EMI sources

A completely automatic near-field mapping system has been developed within IRSEEM (French research institute for electronic embedded systems) in order to determine the electric field radiated by electronic systems. This test bench uses a 3D probe positioning system to make accurate measurements. The paper presents a validation of the test bench on a microstrip line and experimental results realized on a diode limiter function.

New Behavioral Modeling for DC Motor Armatures Applied to Automotive EMC Characterization

This paper presents a high-frequency modeling method of direct current motor armatures dedicated to low-voltage automotive applications. The proposed model is based on a behavioral approach, which permits to reproduce impedance measurements. It takes into account some physical features and phenomena related to the motor armature. The influence of the skin effect in the windings, the magnetic field penetration in the core, and the armature manufacturing systematic error in the impedance evolution is considered with this model. The model was first developed from that of a basic iron core inductor and improved afterward in order to cover a high frequency range (from dc up to 1 GHz). Several identification methods were used to quantify the model parameters. Furthermore, the model was associated to a noise-current generator in order to estimate the conducted disturbances. These last ones are emitted by the motor in the RF range (100 kHz-108 MHz), knowing the operating conditions of current intensity, voltage, and speed.

New Behavioral Modeling of EMI for DC Motors Applied to EMC Characterization

This paper is dealing with the characterization of the electromagnetic compatibility of the direct current (dc) motors. It acts as the complements of the works achieved recently for the modeling of dc motor impedances. The contact mechanisms between the brushes and the collector blades which cause the electromagnetic interferences (EMIs) are explained and modeled. Knowing the operating conditions of the current intensity, voltage, and speed, EMIs are measured and analyzed in radio frequencies from 100 kHz to 108 MHz. The behavioral model proposed is based on Nortons equivalent circuit where the motor is assumed as a current generator representing the EMI source, associated in parallel with its impedance model. Specific identification methods are used to quantify the EMI model parameters. It is shown that the model is in good correlation with the measurement. The model was applied for estimating the conducted EMI generated by a dc motor with its filters, and then, validations with different dc motors were performed.

Postprocessing of Near-Field Measurement Based on Neural Networks

This paper presents postprocessing based on neural network (NN) models to reconstruct the magnetic near-field profile with an improved spatial resolution for one or different frequencies. The models aim at decreasing the time required to perform near-field electromagnetic compatibility (EMC) measurements. The multilayer perceptron (MLP) NNs are used to determine the magnetic near field radiated by passive devices and power electronics components. An optimization method, called the split-sample method, is implemented to determine the structures of the NN. The results obtained with the proposed method are compared with the measurement results. A graphic interface (GUI) is created to simplify the utilization of the developed NN models.

An omnidirectional stereoscopic system for mobile robot navigation

This paper proposes a scheme for a 3D metric reconstruction of the environment of a mobile robot. We first introduce the advantages of a catadioptric stereovision sensor for autonomous navigation and how we have designed it with respect to the Single Viewpoint constraint. For applications such as path generation, the robot needs a metric reconstruction of its environment, so calibration of the sensor is required. After justification of the chosen model, a calibration method to obtain the model parameters and the relative pose of the two catadioptric sensors is presented. Knowledge of all the sensor parameters yields the 3D metric reconstruction of the environment by triangulation. Tools for calibration and relative pose estimation are presented and are available on the authorpsilas Web page. The entire process has been evaluated using real data.