Dipole ring array antenna for circularly polarized pattern

摘要

A NAVSTAR satellite has a navigation antenna array beamed toward the earth. A communications antenna array for communicating with other satellites requires a pattern null near the axis and high gain to the sides with minimum losses. This is achieved with a dipole ring array comprising eight elements surrounding the navigation array. The ring has a diameter of 1.1 wavelength, and is fed with equal amplitudes and a third mode phase progression, which produces good circular polarization in the far field. For a different sized dipole ring, there will still be an optimum phase distribution which will give good circularly polarized patterns.