Thales (Netherlands)

About: Thales (Netherlands) is a company organization based out in Hengelo, Netherlands. It is known for research contribution in the topics: Electromagnetic compatibility & Radar. The organization has 40 authors who have published 52 publications receiving 518 citations. The organization is also known as: Hollandse Signaalapparaten B.V. & Signaal.

A new behavioural model for performance evaluation of common mode chokes

Abstract: A behavioural model for performance evaluation of a common mode choke (CMC) is proposed: the topology and methods used to model the different properties of the CMC are presented. It combines an accurate model of the complex permeability, of the saturation, of leakage inductances and of parasitic capacitances. Inputs needed from the designer are measured values of currents, voltages and impedance of the actual system, and parameters available in literature and/or from manufacturers for the modelled CMC. The behavioural model is essential in simulation of EMI effects.

Risk based EMC for complex systems

Abstract: The rule-based approach, i.e. following electromagnetic interference standards, is the basic methodology assumed to result in electromagnetic compatible systems operating properly in their intended environment. For complex systems we need a smarter approach, based on assessing and controlling the electromagnetic risks. This risk-based approach is described, and applied to naval ships.

Optimal Particle-Filter-Based Detector

Abstract: In this letter, we propose and prove the asymptotic optimality of a particle-filter-based detection scheme. The detection method can be used in a general nonlinear/non-Gaussian signal detection problem. The proposed detection mechanism is based on the likelihood ratio (LR) and thus optimal in the Neyman–Pearson sense, but we approximate the LR based on a particle filter (PF). We show the asymptotic optimality by proving that the PF-based approximation of the LR converges to the true LR as the number of particles increases to infinity. We also discuss the practical and operational implications of the result, the main one being that it is optimal in the sense that no other processing and detection mechanism can have higher probability of detection, while having the same or lower false alarm rate.

Analysis of wide-band infinite phased arrays of printed folded dipoles embedded in metallic boxes

Abstract: A theoretical method is presented to analyze the scan performance of infinite phased arrays of printed folded dipoles embedded in metallic boxes. By using the equivalence principle, each unit-cell is divided into an inhomogeneous interior region and a homogeneous exterior region. The exact dyadic Green's function for both regions is derived. The current distribution on the antenna elements and the corresponding active impedance are found by solving the pertaining integral equations with the method of moments. Numerical results show that the E-plane scan performance is improved significantly by placing the folded dipoles inside metallic boxes. Without the use of additional matching circuits a bandwidth of more than 16% was obtained over a wide scan range. A disadvantage of the use of metallic boxes is the strong appearance of a blind scan angle at the higher frequencies. Measurements of the element pattern of an 1152-element prototype show a very close agreement with the presented theoretical computations.