Anne Louis

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 OF THE OPEN-ENDED COAXIAL PROBE USED FOR NEAR-FIELD MEASUREMENTS IN EMC APPLICATIONS

A completely automatically near-field mapping system is developed within IRSEEM (Research Institute for Electronic Embedded Systems) in order to determine electromagnetic field radiated by electronic systems. This test bench uses a 3D positioning system of the probe to make accurate measurements. The main element of this measurement tool is the probe. This paper presents a characterization of the open-ended coaxial probe which is used to measure the normal component of the electric field.

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.

Transient Response Characterization of the High-Speed Interconnection Rlcg-Model for the Signal Integrity Analysis

This paper is devoted on the characterization method of RF/digital PCB interconnections for the prediction of the high- speed signal transient responses. The introduced method is based on the use of the interconnection line RLCG-model. Theoretical formulae enabling the extraction of the electrical per-unit length parameters R, L, C and G in function of the interconnection line physical characteristics (width, length, metal conductivity, dielectric permittivity ...) are established. Then, by considering the second order approximation of the interconnection RLCG-model transfer matrix, the calculation process of the transient responses from the interconnection system transfer function is originally established. To demonstrate the relevance of the proposed model, microwave- digital interconnection structure comprised of millimetre microstrip line driven and loaded by logic gates which are respectively modelled by their input and output impedances was considered. Then, comparisons between the SPICE-computation results and those obtained from the proposed analytical model implemented in Matlab were made. As results, by considering a periodical square microwave-digital excitation signal with 2Gbits/s rate, transient responses which are very well- correlated to the SPICE-results and showing the degradation of the tested signal fldelity are observed. The numerical computations conflrm that the proposed modelling method enables also to evaluate accurately the transient signal parameters as the rise-/fall-times and the 50% propagation delay in very less computation time. For this reason, this analytical-numerical modelling method is potentially interesting for the analysis of the signal integrity which propagates

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.

MODEL ORDER REDUCTION FOR PEEC MODELING BASED ON MOMENT MATCHING

Accurate and efiective system-level modeling has become necessary to address electromagnetic compatibility (EMC) issues in modern circuit and system design. Model order reduction (MOR) techniques provide a feasibility to approximate complex circuit models with compact reduced-order models. In this paper, an efiective MOR technique entitled multi-point moment matching (MMM) is implemented for the partial element equivalent circuit (PEEC) modeling. Moment information at multiple frequency points is used in this method in order to accurately estimate a given system over an entire frequency range of interest, and for each frequency an enhanced asymptotic waveform evaluation (AWE) is applied to obtain a reduced-order model by constructing a pole-residue representation of the original transfer function. The improvements of conventional AWE in aspects of both moment computation and moment matching can avoid ill-conditioned moment matrices and unstable dominant poles. The complex frequency hopping (CFH) technique is employed to select the multiple expansion points by using a newly developed upward- search algorithm. Numerical simulations of coupled microstrip lines in both frequency and time domain indicate the efiectiveness of the proposed method.

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.