A method of manufacturing an array antenna comprising: a design phase wherein an array layout of said array antenna is synthesized and radiating elements are designed to be arranged according to said array layout; and a phase of physically making said array antenna wherein the radiating elements are arranged according to said array layout. The design phase comprises the steps of: defining a continuous reference aperture; subdividing said continuous reference aperture into a plurality of elementary cells with assigned power levels; determining, within each said elementary cell, a position for at least one maximum efficiency radiating element; determining a size and an aperture field amplitude of each said maximum efficiency radiating element, such that a variation of a cumulative field distribution of the resulting array antenna aperture over each said elementary cell is substantially equal to a variation of a cumulative field distribution of said reference aperture over the same elementary cell, subject to size constraints.