Optimization of stacked vertical dipoles above a ground plane using the genetic algorithm

In this paper the Genetic Algorithm (GA) is used to design and optimize a dual-band antenna system covering the UHF and VHF bands. The system contains two stacked vertical wire dipoles, one for each of the bands, above a perfectly-conducting ground plane. Unlike the case of the GA design of a single-band antenna [1, 2], the mutual coupling between the two dipoles introduces some complications in the design of dual-band antennas. Specifically, in the process of broadbanding one dipole by optimizing its loading and matching network for its own frequency band, it becomes necessary to take into account the influence of the second dipole operating in a different frequency band. It is, therefore, essential to carry out the analysis and the synthesis of the entire coupled system concurrently. This paper proposes a design procedure for the dual-band antenna system that makes initial choices for the antenna configuration on the basis of a systematic screening of the potential candidates, and then goes on to apply the GA in conjunction with the Numerical Electromagnetics Code (NEC4) [3] to meet the specifications for the two operating in a simultaneous manner.