This paper presents a novel optimization method used to design thin wire antennas to approximate any arbitrary antenna gain pattern. These types of antenna designs may be useful for specific tracking-search radars or telecommunication systems trying to maximize the antenna footprint without significant sidelobe power loss. A genetic algorithm (GA) is used to optimize the design of a thin wire antenna to match a predefined antenna pattern. Two different three-dimensional antenna topologies are allowed. The first is the conventional bent long wire or “crooked wire” antenna and the second a “branching tree antenna”. The branching tree antenna resembles the structure of a tree. The advantage of the branching tree topology is that it allows antennas to branch in several directions at each segment end. This paper also describes a systematic approach of developing an objective function for any desired power pattern.