Abstract
Beamforming, namely exciting properly a set of sources whose collective radiation mimics a given pattern, is an inherently inverse problem. Since the inverse design methods are recently being introduced in photonic systems leading to devices of unprecedented efficiency, we reconsider beamforming in this context. Accordingly, flawless beam-shaping is reported for the simple case of multiple emitters placed along a line. The key parameter to fulfill such an objective is the distance between two consecutive antennas which should obey an approximate inequality, securing both diversity and coherence for the emitting patterns. This condition cannot be attained when infinite directivity is demanded; however, ultra-narrow radiation lobes are developed for the suitable, inversely-determined excitations.