Design and optimization of a folded helical meandering line antenna with genetic algorithms

Abstract

This paper summarizes the results of an ongoing design effort to optimize a compact HF antenna using genetic algorithms. A program was developed to implement the genetic algorithm process and used NEC antenna modeling software to analyze the performance of the designs generated in the process. Although this optimization effort is not yet complete, initial results with the GA process have already led to a marked improvement in performance over the original design. It is also noted that within the limits placed on the physical height and width of the antenna, although the resonant frequency was primarily determined by total wire length enclosed within the volume, the quality factor Q was very sensitive to the specific geometry of the wire within the volume. When the effective spherical radius varied only slightly, the overall performance was practically unchanged for all antenna configurations. However, within these constraints on overall volume, optimization can be achieved for lowering the quality factor and increasing the radiation resistance for electrically small antenna. It was also observed that the reduction in Q and increase in resistance obtained through the GA process may allow for some reduction in overall antenna physical volume while achieving similar performance to the original non-optimized design. Future efforts will include experimental verification for optimized designs, reducing the physical size of the antenna, and expanding the input parameters used in the GA process (e.g., length of individual helical elements and the spacing of the meandering lines).