Differential Evolutionary Algorithm for Synthesizing Sum and Difference Pattern in Linear Antenna Arrays with Reduced Design Cost of Feed Network

In this work a new approach to synthesize sum and difference pattern in the radiation pattern of linear antenna arrays is proposed. To reduce the design cost of the feed network of the array for the desired array pattern, only part of the radiating elements are excited non-uniformly whereas the remaining elements are excited uniformly at constant amplitude. The work is illustrated with a 30 elements symmetrically excited linear array. To synthesize the sum pattern, 16 end elements (8 elements at each end) are assumed to be excited non-uniformly whereas for the difference pattern only 16 central elements are perturbed with low Dynamic Range Ratio (DRR). The effectiveness of the Differential Evolution (DE) algorithm is used to synthesize the desired pattern. The DE optimized sum pattern reduces the Side Lobe Level (SLL) to -25.12 dB and the SLL of the corresponding difference pattern is obtained as -16.48 dB. Also the directivity of the synthesized sum and difference pattern are observed as 35.18 dB and 37.76 dB respectively.