Optimum design of Yagi fractal arrays using genetic algorithms

Method of moments, MoM, and the genetic algorithms, GA, are developed to optimize the element spacing and the heights of Yagi fractal arrays. The MoM is used independently for the computation of the current distribution on the array elements, the gain, and impedance characteristics of the array, while the GA is applied to select the heights and the spacing of the elements of the antenna arrays at each iteration. As a result of this optimization a simple Yagi fractal array is obtained with a maximum gain and real part of the input impedance close to 50. Different shapes of Yagi fractal arrays are designed for maximum gain between 10-13 dB.