Sidelobe reduction in linear antenna arrays with corporate-feeds of non-uniform power distribution

A systematic approach to sidelobe reduction of broadside linear antenna arrays using corporate feeds implementing non-uniform excitation is proposed. Only the corporate feeds that consist of equal-power split T-junctions, i.e., the simplest power dividers, are considered. First, for a given particular array aperture, candidate feeds (excitation sets) are searched among excitation sets which might energize the aperture. The search is performed over all realizable excitations using the array factor and the model of excitation amplitudes due to power distribution within the feed. At the second stage, an excitation that provides reduced sidelobes and simple routing is implemented as a microstrip corporate feed. Finally, the entire antenna-feed circuit is tuned and validated using numerical optimization and discrete electromagnetic simulations at the high-fidelity level of description. Our approach offers flexibility in design of linear antenna arrays without introducing extra hardware complications. A case study of a twelve-element microstrip array-feed circuit explains and demonstrates our approach.