Summary
International Symposium on Antennas and Propagation
2010
Session Number:4FB1
Session:
Number:4FB1-3
Relationship between SLL and Steerable Angle of PSO-derived Circular Antenna Array
Nik Noordini Nik Abd Malik, Mazlina Esa, Syarifah Kamilah Syed Yusof, Shipun Anuar Hamzah,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
The design of antennas with directive capability to meet the requirements of minimizing interference and increasing transmission range is one of the enormous concerned in wireless communication technology. Antenna array is one of the alternative methods to realize these antenna characteristics. There are different types of antenna array which depends on the geometrical location of its elements. Techniques for designing antenna arrays can be realized by determining the physical or geometrical layout, and a set of the amplitude and phase of the current excitations of the antenna array [1]. The focus of this work is on the geometrical layout or in simply means the distance of elements. In the uniformly circular antenna array (UCA) with half wavelength distance elements, the steering angle will significantly increases the grating lobes appearance. Additionally, it can causes the outer sidelobe level (SLL) to increase whenever the main beam is steered to any desired angle, which sometimes can be higher than the first SLL. Therefore, in this work, non-uniform circular antenna array (NCA) is designed by optimizing the location elements using stochastic particle swarm optimization algorithm (PSO) [2]. The objectives aim for the steerable desired angle; which maintain low SLL and first null beamwidth (FNBW) during steering method. Several optimization techniques have been proposed in literature which implementing another evolutional optimization algorithm such as genetic algorithm (GA) [8], simulated annealing (SA), and particle swarm optimization (PSO) [9] to deal with NCA. These stochastic algorithms have been used successfully as the optimizer for the antenna design. In array antenna, it has been used to obtain the excitation coefficients and optimize the amplitude, phase, spacing and position of a linear antenna array [3]-[7] and circular antenna array [8], [9]. In this paper, the relationship between the steering angle and the SLL performance is presented. By applying the efficient PSO algorithm [2], the optimum element distance positions have been successfully optimized in dealing with maximum performance of the suppressing SLL and the steering angles. The trade-off performance between the above criterias is shown for different cases of 6-element NCA. The results show that the successful PSO-derived NCA demonstrate superior capability as compared to UCA [1].