A circularly polarized antenna system having improved axial ratio is disclosed.
The antenna system comprises a circularly-polarized antenna, and a high-impedance
buffer surface, surrounding the circularly polarized antenna, and disposed between
the circularly polarized antenna and a ground plane. The width of the high-impedance
buffer surface between the circularly-polarized antenna and the ground plane is
selected to achieve an H-plane radiation pattern substantially identical to an
E-plane radiation pattern over a desired scan angle.