A pattern synthesis method based on Evolutionary Algorithm is presented to generate a dual radiation pattern from a planar array of isotropic antennas. The desired patterns are obtained by finding out optimum set of elements excitations. Flat-top and Pencil beams share a common optimum amplitude distribution among the array elements. Flat-top beam is generated by updating the zero phases with the optimum phases among the elements. 4 bit discrete amplitudes and 5 bit discrete phases have been taken to simplify the design of the feed network. Results clearly show the effectiveness of the proposed method.