Conformal phased array with beam forming for airborne satellite communication

For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. To this end, phased array antennas which are conformal to the aircraft fuselage are attractive. In this paper two key aspects of conformal phased array antenna arrays are addressed: the development of a broadband Ku-band antenna and the beam synthesis for conformal array antennas. The antenna elements of the conformal array are stacked patch antennas with dual linear polarization which have sufficient bandwidth. For beam forming synthesis a method based on a truncated Singular Value Decomposition is proposed

BESTFACT Best Practice Handbook 3

The Best Practice Handbook (BPH) gives an overview about current concepts, strategies and actions in freight transport all over Europe. It is disseminating information on successful projects and practices to increase awareness and share experiences. It is enabling knowledge transfer and supporting transferability for best practices. The third and last Best Practice Handbook focuses on the work done over the entire project, with 157 inventory cases and 60 in-depth analyses. After four years of case collection a wide field of solutions is available. The main findings of the BESTFACT cases are cross-checked and summarised for each of the cluster topics. The consistent form of collection and information provision broadens the structural understanding of best practice cases. The synthesis of cases per topic shows that under consideration of barriers and framework conditions replicable impacts are achievable. Main editors are Martin Ruesch & Simon Bohne (Rapptrans) and Jacques Leonardi (UoW). Project leader is Marcel Huschebeck (PTV)

Integrated field equations methods for the computation of electromagnetic fields in strongly inhomogeneous media

Electromagnetic field theory plays a very important role in present-day technology; examples of technologies based on electromagnetism that are inextricably bound up with every day life are: radar, remote sensing, geoelectromagnetics, bioelectromagnetics, antennas, wireless communication, optics, high-frequency circuits, and so on. In order to be able to develop new applications, and to improve the existing technologies, it is becoming increasingly important that there are methods available that accurately calculate electromagnetic fields. It is becoming particularly important to predict electromagnetic fields in inhomogeneous materials due to ongoing miniaturization of modern integrated circuits (ICs) and their ever-increasing operating frequencies. In the thesis we present the Volume-Integrated Field Equations (VIFE) method and the Surface-Integrated Field Equations (SIFE) method, two novel numerical methods for calculating time-harmonic electromagnetic fields in strongly inhomogeneous media. We calculate the electromagnetic fields with great accuracy for a number of complex 2D and 3D field problems. For instance, the thesis is concluded with the computation of the electromagnetic scattering of a dielectric cube where the domain of computation is truncated by using so-called Perfectly Matched Layers (PMLs) that simulate extension to infinity.Electrical Engineering, Mathematics and Computer Scienc

De Zuid-Oost Veluwezoom: Parels rijgen in de regio

Eindrapport van het Raakproject 'Veluwezoom: parels rijgen in de regio &#39

Computational aspects of 2D-quasi-periodic-green-function computations for scattering by dielectric objects via surface integral eEquations

We describe a surface integral-equation (SIE) method suitable for computation of electromagnetic fields scattered by 2D-periodic high-permittivity and plasmonic scatterers. The method makes use of fast evaluation of the 2D-quasi-periodic Green function (2D-QPGF) and its gradient using a tabulation technique in combination with tri-linear interpolation. In particular we present a very efficient technique to create the look-up tables for the 2D-QPGF and its gradient where we use to our advantage that it is very effective to simultaneously compute the QPGF and its gradient, and to simultaneously compute these values for the case in which the role of source and observation point are interchanged. We use the Ewald representation of the 2D-QPGF and its gradient to construct the tables with pre-computed values. Usually the expressions for the Ewald representation of the 2D-QPGF and its gradient are presented in terms of the complex complementary error function but here we give the expressions in terms of the Faddeeva function enabling efficient use of the dedicated algorithms to compute the Faddeeva function. Expressions are given for both lossy and lossless medium parameters and it is shown that the expression for the lossless case can be evaluated twice as fast as the expression for the lossy case. Two case studies are presented to validate the proposed method and to show that the time required for computing the method of moments (MoM) integrals that require evaluation of the 2D-QPGF becomes comparable to the time required for computing the MoM integrals that require evaluation of the aperiodic Green function

A multilevel Green function interpolation method to efficiently construct the EFIE MoM-matrix for 2D-periodic PEC structures in 3D space

For scattering by perfectly conducting objects in a two-dimensionally periodic setup we employ a surface-integral equation, the Ewald representation of the Green function, and the Method of Moments (MoM). For moderate-size matrices, we observe that the computation time is dominated by the computation of the matrix elements. By employing a multi-level decomposition of the Green function based on Lagrange interpolation on a Chebyshev grid, we demonstrate that the overall computation time can be reduced by 73% compared to the original MoM computation

SIE approach to scattered field computation for 2D periodic diffraction gratings in 3D space consisting of high permittivity dielectric materials and plasmonic scatterers

We describe a surface integral-equation (SIE) method suitable for reliable computation of electromagnetic fields scattered by 2D periodic gratings in homogeneous 3D space in which the gratings may consist of high permittivity dielectric materials and metals. More in particular we brie y describe the formulation, the discretization and efficient evaluation of the Quasi Periodic Green Function (QPGF) and its gradient using Ewald's method. We present a case study to illustrate the method's capability of handling high permittivity dielectric materials and a second case study to demonstrate the effectiveness and indispensability of interpolating the QPGF and its gradient using tables with precomputed values