Directivity optimization for Yagi-Uda arrays of shaped dipoles

A method is presented for the maximization of the directivity of Yagi-Uda arrays whose elements are not straight conductors. The optimum shapes as well as the positions of the array elements are determined, both of which depend on the radius of the conductors. The moment method is used in the optimization process. An example shows that an optimized Yagi-Uda array of three
1.5 \lambda
elements can achieve a maximum directivity of 11.8 dB.