Design aspects of fragmented patch elements for phased arrays

With an idealized feed, fragmented patches with plusmn45deg scan and octave bandwidth are relatively easy to design. However, with a realistic feed the obtainable bandwidth is degraded. One reason is that the vertical feed drastically alters the electric field distribution under the patch, making it more difficult or perhaps impossible for the GA to find an equally good solution. A second reason may be that our present GA is unable to find the global optimum, since GA solutions are sensitive to the particular representation of the degrees of freedom used.