A planar spiral balun applied to a miniature stochastic dipole antenna

A planar spiral balun was developed and fabricated with a stochastic dipole antenna showing a tip-to-tip size reduction of 42% compared to a straight dipole antenna. The desired size reduction of the antenna was achieved through the application of a robust optimization procedure based on genetic algorithms. A moment-method-based solver was used as the balun design tool. The antenna and balun are completely integrated, avoiding the cost and poor performance of more common hybrid (chip & board) techniques. Two separate integrated dipole elements with baluns were constructed; a straight dipole and a miniature genetically optimized stochastic dipole. One-port S-parameter measurements are shown for each design and radiation patterns are shown for the stochastic dipole thereby providing validation for the balun design.