Thinning involves reducing total number of active elements in an antenna array without causing major degradation in system performance. Dynamic thinning is the process of achieving this under real-time conditions. It is required to find a strategic subset of antenna elements for thinning so as to have its optimum performance. From a mathematical perspective this is a nonlinear, multidimensional problem with multiple objectives and many constraints. Solution for such problem cannot be obtained by classical analytical techniques. It will be required to employ some type of search algorithm which can lead to a practical solution in an optimal. The present paper discusses an approach of using genetic algorithm for array thinning. After discussing the basic concept involving antenna array, array thinning, dynamic thinning, and application methodology, simulation results of applying the technique to linear and planar arrays are presented. 1. Introduction An antenna array refers to two or more antenna elements that are spatially arranged and electrically interconnected to produce a directional radiation pattern. The electrical characteristics, orientations, and polarizations of the elements forming part of the array as well as the geometrical arrangement of the array and their interconnections determine the overall performance of the array. Antenna arrays containing large number of elements are frequently used in radar, communication, astronomy, and other systems. In order to reduce the element count, cost, weight, power consumption, and heat dissipation in these systems, thinning is sometimes performed by removing a percentage of array elements according to a suitable strategy. For a fixed antenna size, the thinning produces antenna arrays much cheaper than completely filled arrays, in terms of both hardware and control complexity. Moreover, although by thinning the main lobe width may remain approximately unaltered, there will generally be a reduction in antenna gain and also loss of control over the radiation pattern outside the main beam. Thinning can be considered as a tool for reducing total number of active antenna elements in an antenna array when the main beam is narrow and the demand on the control of radiations outside the main beam is modest. The main concern in the design of such thinned arrays is to find an optimal set of element spacing’s to meet array specifications based on current distribution among the antenna elements. Since the array factor of the thinned array is a nonlinear function of element spacing and there are an infinite number of
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