Unequally excited generalised random binned antenna arrays

It has been recently shown that random arrays paired with a proper excitation strategy can be used to shape the array factor. These random arrays were termed unequally excited totally random arrays (TRAs). This scheme allows to greatly enlarge the class of obtainable patterns, well beyond the classical single beam. However, its main disadvantage is a reduction of the achievable performance, the latter measured in terms of the deviation from the average array factor. In this contribution, a strategy for remedying (even only partially) to such a loss of performance by retaining the same flexibility in shaping the pattern is addressed. To this end, a new scheme for generating random arrays that merges unequal excitations and a suitable generalised binned procedure is introduced. It is shown that this new model of generalised binned arrays always outperforms unequally excited TRAs. In particular, the study is focused on symmetric arrays (for which the elements are deployed symmetrically with respect to the array aperture centre) which allows to get closed-form expressions without invoking some common assumptions that in general do not hold true in practice. The theoretical findings are assessed by several numerical examples for the case of multi-beam array factors.