Radiation Pattern Optimization of a 6 element Yagi-Uda Antenna
This example, optimizes a 6 element Yagi-Uda antenna for higher directivity at zenith (elevation = 90 deg). The design frequency and typical dimensions of the metal structures are chosen for VHF operation . The design of a Yagi-Uda is a challenging task owing to the sensitivity of the pattern to physical parameters. This example will design a Yagi-Uda antenna by using a direct search based optimization approach. The Yagi-Uda antenna is a widely used radiating structure for a variety of applications in commercial and military sectors. Arguably, the most popular use of this antenna was in reception of TV signals in the VHF-UHF range of frequencies . The Yagi is a directional traveling-wave antenna with a single driven element, usually a folded dipole or a standard dipole, which is surrounded by several passive dipoles. The passive elements form the reflector and director, with the name identifying the position relative to the driven element. The reflector dipole is positioned behind the driven element in the direction of the back lobe of the antenna radiation while the director, as the name suggests, is placed in front of the driven element, in the direction where a main beam would form.