Adaptive beamforming synthesis for thinned fractal antenna arrays

Fractal antenna array is a compact and multi-band antenna-element design technique. One of the major challenges of this array design is the possibility of radiation pattern synthesis. In this work, the Least Mean Square (LMS) algorithm is investigated as an adaptive beamforming method in the design of thinned fractal antenna arrays for the first time. This array design is developed by estimating the active fractal array elements corresponding to the desired radiation pattern main lobe and nulls, while maintaining the same Side Lobe Level (SLL) at multiple frequency bands. The capability of the proposed method is demonstrated by considering linear cantor and Sierpinski carpet fractal antenna arrays. The results show that the proposed antenna array design is much superior in terms of multi-band frequency operation, array element reduction, and beamforming accuracy. This reveals the effectiveness of the proposed algorithm as a promising design technique in the smart antenna technology.