An interesting property of the Yagi antenna is that the directors can control the direction of the main beam. Fig. 13 and 14 show the structure that deploys this characteristic to reduce the side lobe levels. The optimized parameter was   which is the shift on the X axis of each Yagi director in respect to the one below. This allowed having a single parameter of optimization. The ratio of three was chosen arbitrarily and allows having the two inner branches not to close from each other and from the outer branches, throughout the optimization. Fig. 15 shows the effect of the parameters on the radiation pattern