DESIGN OF FULLY DIGITAL CONTROLLED RECONFIGURABLE DUAL-BEAM CONCENTRIC RING ARRAY ANTENNA USING GRAVITATIONAL SEARCH ALGORITHM

Abstract

In this paper, we propose an optimization method based on Gravitational Search Algorithm (GSA) for design of reconflgurable dual-beam concentric ring array of isotropic elements with phase only control of flve-bit digital phase shifters. The problem is to flnd a common radial amplitude distribution using four-bit digital attenuator that will generate three difierent types of broadsided beam pair in vertical plane: a pencil/pencil beam pair, a pencil/∞at-top beam pair and a ∞at-top/∞at-top beam pair (sector pattern) with desired value of side lobe level, flrst null beam width and ripple. The two patterns difier only in radial discrete phase distribution while sharing a common discrete radial amplitude distribution. The optimum sets of four- bit discrete radial amplitude distribution generated by four-bit digital attenuators and flve-bit discrete radial phase distribution generated by flve-bit digital phase shifters for obtaining dual radiation patterns are computed by Gravitational Search Algorithm.