As the automotive industry advances through technology integration, components are designed to operate at increasingly higher frequencies. Consequently, there will be an increasing demand for automotive electromagnetic compatibility (EMC) testing. Testing and certification institutes, such as RISE Research Institutes of Sweden AB, thus face an urgent need to develop innovative solutions that can effectively address this growing demand. This master thesis work concerns one EMC test method in particular - the On-board Transmitter (OBT). This is a test which mainly serves to test the immunity of vehicles to electromagnetic disturbances originating from hand-held devices. The conventional test is performed in an anechoic chamber and the methodology requires a substantial amount of time. The intent with this work is thus to evaluate the potential of a novel OBT method where the concept of a reverberating chamber is applied inside the vehicle compartment. Initially, the conventional method was examined from two mock-ups of idealized cases, and it was observed that the electromagnetic field in the near-field region of the transmitter is highly erratic. It was also concluded that the test setup is particularly sensitive to the polarization of the transmitter. With these findings in mind, the accuracy of the conventional method was deemed questionable. Evaluation of the proposed Reverberating On-board Transmitter (ROBT) method proved that the electromagnetic environment inside the vehicle did not resemble a perfect reverberation chamber. Which was expected as the absorbing material such as seating and upholstery likely prevents a field distribution similar to that in a reverberation chamber. Still, the intent of the project was to find a test method superior to the conventional method and it can be stated that the ROBT method is an adequate option due to its capacity to expose the electronics to isotropic radiation. This was found from two measures which this thesis introduces: expected isotropicity eiso, a relative measure of the electric field components and DDoF, a quantification of the spatial distribution inside a reverberation chamber. / EMC VERifiering av Autonoma fordon i modväxlad kammare (EMCVERA)

The multi-conductor lossy transmission-line model and finite element simulation tool are used to analyze the high-frequency attenuator and the DM transmission-line EMI filter. The insertion gain, transfer gain, current distribution, and input impedance of the filter under a nominal design are discussed. In order to apply the transmission-line EMI filter to power electronics systems, the performance of the filter under different dimensions, material properties, and source and load impedances must be known. The influences of twelve parameters of the DM transmission-line EMI filter on the cut-off frequency, the roll-off slope, and other characteristics of the insertion gain and transfer gain curves are investigated. The most influential parameters are identified. The current sharing between the copper and nickel conductors under different parameters are investigated. The performance of the transmission-line EMI filter under different source and load impedances is also explored. The measurement setups of the DM transmission-line EMI filter using a network analyzer have been discussed. The network analyzer has a common-ground problem that influences the measured results of the high-frequency attenuator. However, the common-ground problem has a negligible influence on the measured results of the DM transmission-line EMI filter. The connectors and copper strips between the connectors and the filter introduce parasitic inductance to the measurement setup. Both simulated and measured results show that transfer gain curve is very sensitive to the parasitic inductance. However, the insertion gain curve is not sensitive to the parasitic inductance. There are two major methods to reduce the parasitic inductance of the measurement setup: using small connectors and applying a four-terminal measurement setup. The transfer gain curves of three measurement setups are compared: the two-terminal measurement setup with BNC connectors, the two-terminal measurement setup with Sub Miniature version B (SMB) connectors, and the four-terminal measurement setup with SMB connectors. The four-terminal measurement setup with SMB connectors is the most accurate one and is applied for all the transfer gain measurements in this dissertation. This dissertation also focuses on exploring ways to improve the performance of the DM transmission-line EMI filter. Several improved structures of the DM transmission-line EMI filter are investigated. The filter structure without insulation layer can greatly reduce the thickness of the filter without changing its performance. The meander structure can increase the total length of the filter without taking up too much space and results in the cut-off frequency being shifted lower and achieving more attenuation. A prototype of the two-dielectric-layer filter structure is built and measured. The measurement result confirms that a multi-dielectric-layer structure is an effective way to achieve a lower cut-off frequency and more attenuation. This dissertation proposes a broadband DM EMI filter combining the advantages of the discrete reflective LC EMI filter and the transmission-line EMI filter. Two DM absorptive transmission-line EMI filters take the place of the two DM capacitors in the discrete reflective LC EMI filter. The measured insertion gain of the prototype has a large roll-off slope at low frequencies and large attenuation at high frequencies. The dependence of the broadband DM EMI filter on source and load impedances is also investigated. Larger load (source) impedance gives more attenuation no matter it is resistive, inductive or capacitive. The broadband DM EMI filter always has more high-frequency attenuation than the discrete reflective LC EMI filter under different load (source) impedances. / Ph. D.

Le contexte d’étude est celui de la Compatibilité ÉlectroMagnétique (CEM). L’objectif de la CEM est, comme son nom l’indique, d’assurer la compatibilité entre une source de perturbation électromagnétique et un système électronique victime. Or, la prédiction de ces niveaux de perturbation ne peut pas s’effectuer à l’aide d’un simple calcul analytique, en raison de la géométrie qui est généralement complexe pour le système que l’on étudie, tel que le champ à l’intérieur d’un cockpit d’avion par exemple. En conséquence, nous sommes contraints d’employer des méthodes numériques, dans le but de prédire ce niveau de couplage entre les sources et les victimes. Parmi les nombreuses méthodes numériques existantes à ce jour, les méthodes Multi-Domaines (MD) sont très prisées. En effet, elles offrent la liberté aux utilisateurs de choisir la méthode numérique la plus adaptée, en fonction de la zone géométrique à calculer. Au sein de ces méthodes MD, la « Domain Decomposition Method » (DDM) présente l’avantage supplémentaire de découpler chacun de ces domaines. En conséquence, la DDM est particulièrement intéressante, vis-à-vis des méthodes concurrentes, en particulier sur l’aspect du coût numérique. Pour preuve, l’ONERA continue de développer cette méthode qui ne cesse de montrer son efficacité depuis plusieurs années, notamment pour le domaine des Surfaces Équivalentes Radar (SER) et des antennes. L’objectif de l’étude est de tirer profit des avantages de cette méthode pour des problématiques de CEM. Jusqu’à maintenant, de nombreuses applications de CEM, traitées par le code DDM, fournissaient des résultats fortement bruités. Même pour des problématiques électromagnétiques très simples, des problèmes subsistaient, sans explication convaincante. Ceci justifie cette étude. Le but de cette thèse est de pouvoir appliquer ce formalisme DDM à des problématiques de CEM. Dans cette optique, nous avons été amenés à redéfinir un certain nombre de conventions, qui interviennent au sein de la DDM. Par ailleurs, nous avons développé un modèle spécifique pour les ouvertures, qui sont des voies de couplage privilégiées par les ondes, à l’intérieur des cavités que représentent les blindages. Comme les ouvertures sont, en pratique, de petites dimensions devant la longueur d’onde, on s’est intéressé à un modèle quasi-statique. Nous proposons alors un modèle, qui a été implémenté, puis validé. Suite à ce modèle, nous avons développé une méthode originale, basée sur un calcul en deux étapes, permettant de ne plus discrétiser le support des ouvertures dans les calculs 3D. / The context of the study is the ElectroMagnetic Compatibility (EMC). Principal aim of the EMC is to ensure the compatibility between an electromagnetic perturbance source and an electronic device victim. Unfortunately, the perturbation levels prediction can not be made using an analytic formula, because the geometry which is generally complex for the interesting system, for example the field inside an aircraft’s cockpit. Therefore, we are contrained to use numerical methods, to be able to evaluate this coupling level between sources and victims. Among several existing numerical methods, Multi-Domains (MD) methods are very interesting. They offer to users the freedom to choose the most powerfull numerical method, in terms of the geometrical zone evaluated. With the MD methods, « Domain Decomposition Method » (DDM) has the avantage of decouplingeach of theses areas. Therefore, DDM is very interesting, compared to other methods, in particular on the numerical cost. ONERA keeps on developing this method, which has not stop showing his efficiency since several years, in particular in Radar Cross Section (RCS) and antennas. The objective of this study is to take the benefits of this method for EMC problems. Up to now, several EMC applications treated by the DDM code provided results strongly noisy. Even for with very simple electromagnetic cases, some problems remained without convincing explanations. This justifies this study. The aim of this thesis is to can be able to apply DDM formalism to EMC problems. Then, we have been induced to redefine a number of conventions which are involved in the DDM. Otherwise, we have developed a specific model for the apertures which are privilegied tracts of the coupling by the penetration of waves inside cavities (shieldings). As the apertures have in practice smaller dimensions compared to the wavelength, we have been interested to a quasistatic model which was developped, implemented and validated. Following this model, we have developed an original method, based on a two step calculation, able to do not discretize the apertures support in 3D computations.

This thesis deals with the evaluation of accuracy of measurement and achieving the required accuracy level. This includes global analysis of the uncertainty evaluation, the calibration interval design and the creation of confirmation system. Basis of this work is in identification of all possible problems, which may occur during evaluation of accuracy and achieving the required accuracy level. The analysis is followed by suggested solutions for identified problems. It means namely the selection of probability distribution in case of uncertainty type A, evaluation of degrees of freedom in case of uncertainty type B, nonlinear correlation of input values, evaluation of coverage factor, the choice of method for calibration interval design and the procedure for meeting all metrological confirmation requirements. The last part of the thesis is practical measurement and result evaluation in the field of surge protection devices. This chapter demonstrates conclusions from the syntactical part.