Radiation performance evaluation and improvement of a pair of dipoles over a ground plane

The performance and radiation mechanism of a two element elliptical dipole array feed is investigated in detail. The performance metric considers both the maximum cross-polarization level, which is a function of the axial symmetry and cross-polarization of the feed, and the efficiency performance when evaluated on a general reflector system. It is shown that for a two element dipole array to achieve optimum performance the dipoles need to be perfectly circular and the dipole lengths need to be longer than a half wavelength to allow for a second order current mode to coexist with the fundamental mode.