Directivity optimization of fractal antenna arrays using PSO algorithm

Self-similarity property of fractal shapes allows fractal antennas to be compact, multiband, or even wideband. Applying fractals to antenna arrays also develops multiband or broadband arrays. In this paper, we have investigated the multiband behaviour of fractal antenna arrays based on cantor set linear generators, which is impossible for classical arrays to achieve. After that, we have optimized the designed structure for maximum directivity using Particle Swarm Optimization (PSO) algorithm, both for theoretical and full-wave cases. A comparison between two methods is also included. This comparison helps to figure out that analytical formulas for fractal arrays are not only super-fast, but also completely precise despite of their simple form and hence their results are completely reliable and accurate.