Hindawi Publishing Corporation International Journal of Antennas and Propagation Volume 2013, Article ID 713680, 9 pages http://dx.doi.org/10.1155/2013/713680 Research Article Design of Fully Digital Controlled Shaped Beam Synthesis Using Differential Evolution Algorithm D. Mandal, 1 A. Chatterjee, 2 and A. K. Bhattacharjee 3 1 Department of Electronics and Communication Engineering, Bengal College of Engineering and Technology, West-Bengal, Durgapur-713212, India 2 Department of Electronics and Communication Engineering, Dr. B. C. Roy Engineering College, West-Bengal, Durgapur-713206, India 3 Department of Electronics and Communication Engineering, National Institute of Technology Durgapur, West-Bengal, Durgapur-713209, India Correspondence should be addressed to D. Mandal; deb.mandal22@gmail.com Received 20 August 2013; Revised 3 October 2013; Accepted 3 October 2013 Academic Editor: Dau-Chyrh Chang Copyright © 2013 D. Mandal et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A shaped beam synthesis from a concentric ring array has been presented. Two diferent cases are considered. In the irst case, a lat-top beam pattern and, in the second case, a cosec 2 beam pattern have been generated. In both the cases, it has been ensured that the obtained beam patterns are not restricted in any single predeined -cut of the patterns; rather, their characteristics are retaining within a range of predeined -planes with some minor variations. he desired beam pattern under each of the individual case is obtained by inding optimum discrete excitations of the array elements. he optimum 4-bit amplitudes generated by four-bit digital attenuators and 5-bit phases generated by 5-bit digital phase shiters are computed using Diferential Evolution (DE) Algorithm. To illustrate the efectiveness of DE, the two beam patterns with speciied characteristics are computed from the same array using Particle Swarm Optimization (PSO) algorithm and Genetic algorithm (GA) by inding out optimum discrete excitations among the elements. Results clearly show the superiority of DE over PSO and GA to handle the presented problem. 1. Introduction In mobile, satellite, and radar communication the impor- tant parameters are signal quality, system coverage, spectral eiciency, and so forth. To achieve these, eicient antenna design is the primary requirement. Antenna array synthesis is required to ind radiation patterns from diferent array geometry and make these obtain patterns closer to their desired patterns either by varying its elements amplitude and phase or by reconiguration of the array geometry. In various applications shaped beams are oten required but major problems faced by shaped beams are high side lobe level and ripple. To minimize high sidelobe and ripple, an eicient evolutionary optimization algorithm has been chosen which is able to ind out 4-bit optimum discrete elements amplitude and 5-bit optimum discrete phases of the array elements to achieve the desired shaped beam. Several approaches reported in the literature for generating shaped beams [1–6] are as follows. Azevedo proposed a technique based on FFT to generate shaped beams of cosec and lat-top pattern from a linear array antenna through the control of nonuniformly samples of the array factor, both in amplitude and phase [3]. Lei et al. generate low sidelobe cosecant square-shaped beam from linear antenna array by inding optimum amplitudes and phases of the array elements using the modiied least square method [4]. Chatterjee et al. [5] proposed a technique based on inding optimum phases of the array elements modifying which over existing “zero” phases generates two diferent patterns. he search has been carried out using Gravitational Search Algorithm (GSA) [5]. In [6], a new technique has been proposed by Chatterjee et al. for obtaining dual beam pair where the states (“on/of ”) of the array elements are modiied using Firely Algorithm (FA) for generating two diferent beam pairs. he method greatly simpliied the design of the feed network [6]. he paper presents shaped beam synthesis of two ring concentric array of isotropic elements. Two diferent cases