Synthesis of a Near-Optimal High-Gain Antenna Array With Main Lobe Tilting and Null Filling Using Taguchi Initialized Invasive Weed Optimization

A near-optimal base-station antenna array synthesis
suitable for broadcasting applications is presented. The array is
required to provide a high-gain radiation pattern with a main
lobe slightly tilted from the horizontal plane and null filling
inside an angular sector under the main lobe. To satisfy the
above requirements, a novel invasive weed optimization (IWO)
variant called Taguchi initialized IWO (TI-IWO) is proposed
in this paper. In TI-IWO, the Taguchi’s optimization method
is employed to initialize effectively the positions of the weeds
used by the IWO method. In this way, the fitness function starts
from lower values and, thus, the TI-IWO method finds better
near-optimal solutions than the conventional IWO method. The
proposed method has been applied to linear arrays. Due to its
easy implementation in practice, a uniform-amplitude excitation
distribution is considered to be applied on the array elements.
Two cases of isotropic source arrays are studied under specific
requirements for maximum possible gain, main lobe tilting, and
null filling. Also, the TI-IWO method is applied to optimize
realistic cases of collinear wire dipole arrays in front of a mast
under the same requirements and an additional one concerning
the impedance matching of all the dipoles.