Abstract-In the present paper, a combined method of auxiliary sources (MAS)-reaction matching (RM) approach is presented for the analysis of arrays of arbitrarily located cylindrical dipoles. It is shown that the addition of auxiliary monopole terminal sources to each array element results in a superior solution with regard to the numerical stability of the computed quantities, the behavior of the current distributions of the array elements and the resulting errors of the electric field boundary condition. Numerical results are presented for various representative array configurations, in order to illustrate the features of the proposed method and exhibit its advantages over conventional Method of Moments (MoM) schemes, especially in cases of moderately large-scale arrays. Finally, a few concluding remarks are discussed.

A genetically optimized technique that fully automates the potentially laborious allocation of the auxiliary monopoles for the method of auxiliary sources (MAS) is presented for the problem of electromagnetic (EM) scattering by isotropic dielectric cylinders with various cross sections. The proposed technique uses as input information not only the geometry of the scatterer but also the exciting field and the material properties of the cylinders are implicitly taking part in the optimization procedure. The resulting auxiliary surfaces, where the simulating monopoles are situated, are appropriately adapted to the original boundary surface and the MAS modeling is greatly facilitated. In addition, certain considerations are taken into account in order to avoid undesirable numerical dependencies between the fictitious monopoles. Finally, the accuracy of the numerical method combined with overdetermined systems of equations is examined for isotropic cylinders of various geometries and dielectric characteristics.Index Terms-Boundary value problems, electromagnetic (EM) scattering, genetic algorithms (GAs), method of auxiliary sources.

No abstract

The use of the reverberation chamber for performing electromagnetic compatibility (EMC) tests and antenna measurements is examined in this article. This kind of chamber exhibits a significant number of advantages compared to the other commonly used test sites. Its low cost, compact, and easily built structure simultaneously appears to host a very “convenient” electromagnetic environment inside the enclosure, with regard to the requirements that are posted by the standard that is followed during the EMC or any other type of test such as antenna measurements. More specifically, antenna radiation efficiency measurements prove to be satisfactorily performed through the use of a reverberating enclosure, as well as other antenna parameters (e.g., input impedance) tests. The basic characteristics of such a structure are presented with regard to the recently introduced IEC 61000‐4‐21 specification and studies available in the literature. The field uniformity requirements are being extensively described, as well as ways of improving the achieved uniformity. The field inside a reverberating enclosure is statistically characterized with the use of the models proposed in the literature, which are experimentally verified. The use of the reverberation chamber at relatively low frequencies is presented, together with its ability to store large amounts of energy. Finally, the different ways of operating a reverberation chamber are described with regard to which of its features is (are) needed for each instance. The whole presentation marks out the usefulness of the reverberation chamber for performing electromagnetic compatibility tests as well as antenna measurements.

No abstract