In the field of pattern synthesis, the design of arrays to synthesis optimized sum and difference patterns in a successive manner is an important problem in most of the radars. Although several researchers published many papers in the open literature, investigations are made by the authors to design arrays of discrete radiators using a well-formulated Genetic Algorithm (GA). The practical constraints are taken into account to design an amplitude distribution to produce the sum pattern with desired side lobe levels without broadening the main beam. Such sum patterns are found to be very useful in high-resolution radars where the EMI problems are also addressed. In IFF radars, both sum and difference patterns are extremely useful to distinguish between friendly aircraft and enemy aircraft. Such patterns are conventionally produced involving two antennas. One is a directional antenna and another is an omnidirectional antenna. However, in the present work, they are generated using only one directional antenna. The patterns with a deep null in the boresight direction and difference lobes with a high slope are produced with an antiphase excitation to one-half of the array.