Analysis of circular polarization of the Quadrifilar Helix Antenna in the presence of ground plane for LEO satellites

In this research paper, circular polarization of Quadrifilar Helix Antenna (QHA) is investigated under the effects of large fixed metallic ground plane. Variations in the height of QHA above the ground plane affect the circular polarization of QHA. It is noted that boresight axial ratio and 3dB axial ratio beamwidth of QHA fluctuate as height of the QHA ascends above the reference ground plane. Deployment of QHA between the heights of 0.57 λ to 0.7 λ generates 3dB axial ratio beamwidth that is broader than 100°. Input characteristics of QHA are also investigated for varying sized finite ground planes. Excellent circular polarization and wide 3dB axial ratio beamwidth support deployment of QHA on decks of Low Earth Orbit (LEO) satellite for reliable communication.