In this paper, the exact differential surface admittance (DSA) operator for scattering analysis of a homogeneous dielectric sphere is constructed. By utilizing two sets of orthogonal vector spherical harmonics as the basis functions for a Galerkin Method of Moments, the operator in question is obtained analytically. In comparison with the Mie series solution for a tangential electric dipole as source, a combination of the electric field integral equation and the DSA is shown to produce the same result within 12 digits of accuracy, laying the foundations for a subsequent analysis into the operator's fundamental properties.

In this contribution, the exact solution of the electric field integral equation (EFIE) combined with the differential surface admittance (DSA) operator is presented for scattering at a homogeneous dielectric sphere. By employing a Galerkin Method of Moments with two complete sets of orthogonal vector spherical harmonics as basis functions, both operators involved are constructed with closed expressions. By comparing to the classic Mie series solution for illumination by a radial electric dipole, the DSA - EFIE approach is confirmed to yield the exact solution within 12 digits of accuracy.

Multiconductor transmission lines (MTL), or multiconductor buses as they are often Called, are found in almost every electrical packaging technology and on every technology level from digital chips, over monolithic microwave integrated Circuits to multichip modules, boards, and backplanes. This chapter describes the circuit modeling in the frequency domain of uniform MTL based on the Telegrapher's equations. The cross section of the MTL is small with respect to the relevant wavelengths, the longitudinal field components can be neglected and the transversal field components can be found from the solution of an electrostatic or magnetostatic problem in the cross section of the MTL. The chapter examines the Capacitance, inductance, resistance, and conductance matrices together with the characteristic impedance matrix of the Coupled transmission line model. In the case of linear loads and drivers, frequency domain methods in combination with Fourier transform techniques are certainly most effective.

A new model order reduction technique is presented which preserves passivity and non-expansivity. It is a projection-based method which exploits the solution of linear matrix inequalities to generate a descriptor state space format which preserves positive-realness and bounded-realness. In the case of both non-singular and singular systems, solving the linear matrix inequality can be replaced by equivalently solving an algebraic Riccati equation, which is known to be a more efficient approach. A new algebraic Riccati equation and a frequency inversion technique are also presented to specifically deal with the important singular case. The preservation of Markov moments is also guaranteed by the judicious choice of a projection matrix. Three pertinent examples comparing the present approach with positive-real balanced truncation show the strength and accuracy of the present approach. (C) 2010 Elsevier B.V. All rights reserved.

This paper describes an accurate method to discretize the Dirichlet-to-Neumann boundary operator for a convex polygonal conductor. The technique is based on an expansion of the boundary value of the current density. Because the corresponding expansion functions exhibit the exact current behavior inside the conductor, they ensure a very good accuracy up to skin effect frequencies. In combination with a classical boundary integral method and the Method of Moments, the Dirichlet-to-Neumann technique allows for a direct determination of the resistive and inductive properties of transmission line configurations constructed from these conductors, as is illustrated with some numerical examples.

We present results about the apparently statistical behaviour of electromagnetic fields in an overmoded two-dimensional lossless cavity in which a stirrer element is moved. These results are obtained from a non-statistical simulation and this behaviour is analysed using the correlation function for the stirrer angular position.

A microwave nondestructive testing technique to measure the steel fiber content in hardened concrete slabs is presented. The technique is based on an open-ended coaxial probe reflectometry method for measuring the effective permittivity of the steel fiber reinforced concrete and on a classical homogenization approach for determining the fiber content. Two different full-wave models for the probe-aperture admittance as a function of the permittivity are applied: a spectral domain model for the forward problem and a rational function approximation for the inverse problem. A Maxwell-Garnett type of mixing rule is derived for randomly oriented conducting prolate spheroids in a dielectric host medium. A coaxial probe has been constructed, calibration aspects are discussed, and experimental results are presented for concrete slabs with various fiber contents. It can be concluded that the presented technique is a promising one.

De visitatiecommissie Elektrotechniek heeft een eerste conceptversie van haar rapport afgewerkt. De leden van de OCE en de werkgroep visitatie krijgen de kans om hier opmerkingen over te formuleren. De voorzitter had ter voorbereiding reeds een aantal tekstuele en inhoudelijke opmerkingen geformuleerd en aan alle betrokkenen voorgelegd. Ter zitting worden nog een aantal bijkomende opmerkingen geformuleerd. De voorzitter zal een document opstellen voor de visitatiecommissie dat al deze opmerkingen bevat. (bijgevoegd in bijlage). Ook wordt de vrees uitgedrukt dat de samenvattende tabel teveel gewicht zou krijgen. Het gevaar zou hierbij kunnen bestaan dat de lezers van het visitatierapport enkel deze tabel zouden bekijken zonder de begeleidende tekst te lezen. De meeste leden vinden dat deze tekst toch een voldoende genuanceerd beeld van de eigenlijke situatie geeft. 2. Kristallografie Op dit moment is het vak 'Kristallografie' (3 SP, lesgever R. De Gryse) een optievak in de BE in de optie Micro- en optoëlektronica. Dit vak werd vroeger ook aangeboden aan de studenten BN. Door een recente programmahervorming in de BN bestaat dit vak niet meer in de BN. Als gevolg hiervan bestaat dit vak enkel nog als optievak in de BE. De voorzitter van de verantwoordelijke vakgroep (Prof. P. Clauws) stelt voor om dit vak ook in de BE af te schaffen. Eventueel kan het vak "Kristallografie I" uit de tweede kandidatuur Natuurkunde (4 SP, lesgever Dirk Poelman) dan als nieuw optievak aangeboden worden. Het vak 'Kristallografie I' komt voor wat betreft inhoud grotendeels overeen met het vak 'Kristallografie'. Dit vereist een programmahervorming in de BE. In de bespreking hierover wijst de studentenvertegenwoordiging erop dat gewoon schrappen van 'Kristallografie' als optievak de keuzemogelijkheden binnen de optie micro- en optoëlektronica teveel zou beperken. Als dit vak verdwijnt moet het zeker vervangen worden door 'Kristallografie I'. Enkele leden suggereren een alternatieve oplossing: het vak 'Kristallografie' blijft gewoon bestaan maar vanaf nu met lesgever Dirk Poelman. Vermits de inhoud van 'Kristallografie' en 'Kristallografie I' bijna identiek is stelt dit geen praktisch probleem omdat de lessen voor deze vakken gezamenlijk gegeven kunnen worden. Op deze manier is deze kwestie zowel praktisch als administratief opgelost. Een tegenargument tegen dit scenario is dat de overzichtelijkheid enigszins vertroebeld wordt. Dit zou echter slechts enkele jaren duren omdat dan de grootschalige Masters hervorming in voege zou komen. Verscheidene leden vrezen dat er in de overgang naar de nieuwe Masters structuur nog vele gelijkaardige situaties zullen opduiken die dan telkens een programmahervorming zouden vereisen. Gebaseerd op deze elementen beslist de OCE om het vak 'Kristallografie' niet af te schaffen in de BE. De voorzitter zal contact opnemen met de betrokken vakgroep om de hierboven beschreven oplossing te organiseren.

In this paper, both simulations and measurements are used to explore the propagation properties of ultrahigh-frequency (UHF) waves traveling through building structures and, in particular, windows. The propagation influence of several features of a typical window structure is examined, including the electrical properties of the surrounding wall, the homogeneity and roughness of this wall, and the incidence angle of the UHF wave. In these studies, ray tracing is benchmarked against both narrow-band measurements and the results of a full-wave moment method technique. Some of the inherent limitations of ray tracing are assessed and corrective methods are proposed in order to improve its accuracy.

A new automated circuit-modeling tool is presented for arbitrary planar transmission lines. The tool builds compact, parameterized, analytical models based on multiple full-wave 2D electro-magnetic (EM) simulations. The transmission line parameters are stored as a multidimensional function of frequency and geometrical parameters. The modeling algorithm combines adaptive data selecting and modeling techniques. The circuit models combine EM-accuracy and generality, and circuit simulation speed and flexibility.

In this paper, we analyze the scattering at discontinuities in cylindrical waveguides, starting from a vectorial eigenmode expansion and by introducing perfectly matched layer (PML) boundary conditions. The structure under study is enclosed in a metal cylinder to discretize the radiative mode spectrum, while the coating of this cylinder with PML vastly reduces the influence of parasitic reflections at the metal. This allows for a model that is both faster and more accurate than previous models.