engleski

Moment method analysis of spherical structures

The goal of this paper is to explain the method of analysis of spherical structures, either antennas or scatterers, by means of the Method of Moments. Curved structures in general present a big challenge to all the electromagnetic computational methods known today. However, for certain geometries, such as the spherical one, the difficulties can be overcome by applying Moment Method in spectral domain. In the spectral domain approach, a three-dimensional electromagnetic problem is transformed into an infinite series of much simpler one-dimensional problems by means of the vector-Legandre transformation. Each of these simpler problems is resolved by means of the Method of Moments and the final result is then obtained by the inverse transformation. The first part of the thesis describes the principles of the Method of Moments and of the spectral domain approach, which are used in the analysis. The second part applies the exposed theory to the particular case of interest, namely the analysis of spherical patch antennas and frequency selective surfaces, and discusses all relevant issues and particularities involved when treating the problem in a spherical coordinate system. To verify the presented theory, the results obtained with home-developed software are compared to those obtained with commercially available software and/or with measurements.

method of moments; spectral domain; vector Legandre transformation; patch antenna; spherical arrays; frequency selective surfaces

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