Abstract: “Modern communication systems employ antenna arrays for enhanced coverage and efficiency. Such arrays need to exhibit low peak sidelobe level (PSLL) and the capability of positioning multiple asymmetrical mulls. In this paper, modified Invasive Weed Optimization (IWO) algorithm is used to estimate the complex elemental excitations required for achieving multiple nulls in specified directions while maintaining PSLL below the detectable range of -40dB. The novelty of the proposed approach is in the application of a constraint-based static penalty function during optimization of the array. The static penalty function is able to put selective pressure on the PSLL, the first null beam width (FNBW) or the accurate null positioning as desired by the application at hand lending a high degree of flexibility to the synthesis process. Several numerical results of periodic array patterns with the imposed asymmetrical multiple null conditions are presented to illustrate the performance of the propos”

Keywords: Linear antenna array; invasive weed optimization; static penalty function; side lobe level; asymmetrical nulls; null steering.