Optimization of virtually aperiodic linear sparse arrays

Multi-port multi-mode antenna elements have the ability to move their phase centers and modify their radiation patterns electronically. Arrays composed of such elements are referred to as virtually aperiodic arrays in this paper. Herein, optimization of the mode excitation coefficients in virtually aperiodic sparse linear arrays is proposed, by introducing novel design constraints with the aim of synthesizing wide-angle scanning, reconfigurable patterns, with grating/side lobe reduction. A dual-mode patch antenna is used for demonstration purposes. An efficient convex optimization based algorithm is adopted to optimize the excitation weight at each element mode port, while considering the mutual coupling effects. Through full-wave simulations, the effectiveness of the optimization in suppressing the unwanted radiation and adapting to different fields-of-view is shown. A novel investigation on the impacts of defining different mode excitation ratios on the radiation pattern characteristics is conducted.