DESIGN OF MULTI-BEAM RHOMBUS FRACTAL ARRAY ANTENNA USING NEW GEOMETRIC DESIGN METHODOLOGY

Fractal array antenna design methodology is an artistic type of design methodology. Hence fractal array antennas are also called as artistic array antennas. This article proposes a concentric elliptical ring sub array generator geometric design methodology for a methodical expansion of multibeam fractal array antennas. Using this new geometric design methodology, any polygon shape can be constructed. This geometric design methodology provides a systematic approach for multiple beams of fractal array antennas, with unit amplitude constriction, using multi-beam sub arrays and without any increase in hardware complication. In this paper, a four-element rhombus fractal array antenna is examined using a proposed design methodology up to four concurrent iterations and for different eccentric values. Due to the recursive nature of the proposed methodology, the rhombus fractal array antenna shows multi-beam performance with abatement of beam width and better side-lobe levels. In the third and fourth iterations of the rhombus fractal array with expansion factor two, beamwidth reached single digit values of 7.2◦, 3.6◦ with side-lobe level angles of 15.5◦ and 8.1◦, respectively. The behavior of the proposed array shows better performance than four-element fractal array antenna generated by concentric circular subarray generator. The proposed fractal array antennas are analyzed and simulated by MATLAB programming.