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International Journal of Antennas and Propagation
Volume 2015, Article ID 789094, 9 pages
http://dx.doi.org/10.1155/2015/789094
Research Article

Multiobjective Synthesis of Steerable UWB Circular Antenna Array considering Energy Patterns

1CICESE Research Center, Km 107 Carretera Tijuana-Ensenada, 22860 Ensenada, BCN, Mexico
2Universidad Autónoma de Tamaulipas, UAMR-R, Carretera Reynosa-San Fernando, 88779 Reynosa, TAMPS, Mexico

Received 31 July 2015; Accepted 7 October 2015

Academic Editor: Kerim Guney

Copyright © 2015 Leopoldo A. Garza et al. This 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.

Abstract

True-time delay antenna arrays have gained a prominent attention in ultrawideband (UWB) applications such as directional communications and radar. This paper presents the design of steerable UWB circular array by using a multiobjective time-domain synthesis of energy pattern for circular antenna arrays. By this way we avoid individual beamforming for each frequency in UWB spectrum if the problem was addressed from the frequency domain. In order to obtain an energy pattern with low side lobe level and a desired main beam, the synthesis presented is performed by optimizing the true-time delays and amplitude coefficients for the antenna elements in a circular geometry. The method of Differential Evolution for Multiobjective Optimization (DEMO) is used as the optimization algorithm in this work. This design of steerable UWB circular arrays considers the optimization of the true-time exciting delays and the amplitude coefficients across the antenna elements to operate with optimal performance in the whole azimuth plane (360°). A comparative analysis of the performance of the optimized design with the case of conventional progressive delay excitations is achieved. The provided results show a good performance for energy patterns and for their respective power patterns in the UWB spectrum.