Values of the HPBW (top) and AR (bottom) obtained with the two algorithms (SA and KOGAN) using the two element beam patterns f_iso (left) and f_dip (right). The conventions are identical to those of Fig. 3, except for the star symbol, which represents the maximum encountered HPBW value with both optimisation methods, and the horizontal dashed line, which represents a symmetric primary lobe with AR = 1. The hollow squares represent the HPBW values of 13° (left) and 12° (right) for a 4×4 tile with an element spacing of λ/2. For this tile the AR is always equal to one.