Size constraint in design of concentric ring array

In an earlier work a dual-polarized uniform concentric ring array had a diameter of 4 m and 224 spiral antennas, it covered a bandwidth from 1 GHz - 2 GHz. In the present paper, the additional constraint of space is introduced. Keeping the same characteristics of the previous work, the new proposed array has a diameter of 2.2 m (70% space reduction) and 148 antennas (34% element number reduction). The design of the array was carried out using Genetic Algorithms optimization.