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A novel hybrid approach to the power synthesis of mask-constrained shaped beams by means of concentric-ring isophoric arrays is presented. The basis of this procedure is to use the complex aperture distribution obtained by Elliott–Stern method as a starting point of an innovative algorithm that combines a classical density tapering method with a simulated annealing one. The proposed technique allows to outperform the previous procedures. [ABSTRACT FROM AUTHOR]

In this paper, several simple antenna designs based on the use of an active dipole placed above a ground plane with an array of parasitic dipoles are presented. The parasitic dipoles are used to modify the pattern of the active dipole yielding a pencil beam of moderate gain. The use of one active element provides a very simple feeding network that reduces the complexity of the antenna. The proposed technique optimizes the geometry and configuration of both active and parasitic elements. It is shown that the performance of the designed antennas is considerably better than that of a similar antenna without parasitic elements. [ABSTRACT FROM AUTHOR]

A common method of antenna array synthesis uses least-squares approximation to fit the radiation pattern of the array to a set of samples of an ideal desired pattern Fid. However, it has long been known that discontinuities in Fid prevent close approximation, and that sampling a target pattern Ftar that approximates Fid can afford better results. Here we show, for the case of circular planar arrays, that an appropriate target pattern can be obtained by modification of a Taylor pattern for a circular aperture. [ABSTRACT FROM AUTHOR]

Pencil beams may be synthesized for arrays of concentric rings of radiating elements by fitting the field pattern to that of a Taylor pattern for a circular aperture of the same radius. Nonexcitation blockage suppresses inner rings. Here we examine whether this needs to be taken into account in the synthesis procedure. [ABSTRACT FROM PUBLISHER]