Infinitesimal Dipole Model for Dielectric Resonator Antennas using the QPSO Algorithm

The problem of finding a set of infinitesimal dipoles to represent an arbitrary antenna with known near field distribution was considered. By formulating this task as an optimization problem using the directional cosines, the recently introduced quantum particle swarm optimization (QPSO) algorithm was able to successfully obtain good solution. A new boundary condition was introduced to handle the coupling between the directional cosines. The frequency response of the dipole model was also investigated. Although the model was obtained at a single design frequency, the dipoles at the same locations can be used through a wideband scheme by correcting the dipole moments. The correction factor required has been shown to be related to the input impedance of the DRA. A simple procedure is suggested to estimate the correction factor over the frequency band of interest