Abstract: There is provided a new and useful field adjustable sectoral antenna comprising a flat reflecting surface having a front surface and first and second sides; at least one radiating element mounted in front of the front surface; and a pair of side panels each having front and rear edges and inner and outer surfaces; and wherein the panels are mounted with their inner surfaces along respective ones of the first and second sides of the reflecting surface for forward and rearward sliding movement of the side panels relative to the reflecting surface.

Abstract: A surface for an antenna for use in discriminating between horizontal and vertical polarization components of a circularly polorized electromagnetic wave comprises at least one pair of dipoles, one of the dipoles of each pair of dipoles being adapted to receive one component of circular polarization and the other dipole of each pair of dipoles being adapted to receive the other component of circular polarization, and a transmission line extending between and electrically connecting the feed points of the dipoles of each pair of dipoles, whereby an incident circularly polarized electromagnetic wave is reflected when its two polarization components are incident upon their respective dipoles in phase and is transmitted when the its two components are incident upon their respective dipoles 180 electrical degrees out-of-phase.