Yves Schols

Quality Assessment of Computational Techniques and Software Tools for Planar-Antenna Analysis

The goal of this paper is a thorough investigation of the quality of the software tools widely used nowadays in the field of planar-antenna analysis and synthesis. Six simulation tools - five well-known commercial tools and one developed in-house - are compared with each other for four different planar antennas. It is crucial to point out that all possible efforts have been made to guarantee the most optimal use of each of the software packages, to study in detail any discrepancies between the solvers, and to assess the remaining simulation challenges. The study clearly highlights the importance of understanding EM simulation principles and their inherent limitations for antenna designers. Finally, some designing guidelines are provided that also can simplify the initial selection of EM solvers.

Solution of the canonical problem of an elementary dipole on a finite substrate using volume integral equations and volume physical optics

The far field behaviour of an elementary dipole on a one side cladded substrate is analysed as a canonical problem for the study of diffraction effects. The radiation pattern is calculated using three different methods: surface integral equations with multilayered Greens functions, volume physical optics (VPO) and volume integral equations (VIE). Although the finiteness of the substrate is taken into account by both VPO and VIE, these methods are inherently better suited for structures on large respectively small sized substrates. To our knowledge, comparison of VPO and VIE for such a medium sized structure is completely new. It allows us to establish approximate borders and an optimal application area for each method. The simulation results show good agreement. This validates the applicability of both methods for medium sized structures and is at the same time of great importance for estimation of the backward radiation intensity of more complex antenna structures

Efficient calculation of Green's functions for periodic arrays using a new asymptotic extraction technique

The goal of this paper is to extend the effective approach that is used for the calculation of Greens functions (GFs) in planar multilayered structures for a single dipole to the case of a periodic array of dipoles. In both cases the GFs in the spatial domain are calculated via a Fourier transform of the GFs in the spectral domain, which is known in closed form. The transform is expressed in terms of double infinite integrals for a single dipole or a double infinite series for a periodic array. The direct calculation of the transform is not always very efficient. A possible solution consists in the introduction of special asymptotes that annihilate the problematic behavior of the spectral GFs. We demonstrate that it is possible to use the same asymptotes very efficiently in both cases (for a single dipole and a periodic array).