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.

Abstract: There is provided a new and useful radio antenna comprising a mast; a pair of radiating elements mounted on the mast, and being oriented in a plane, and having one end of one element adjacent to one end of the second element; a coaxial feeder the outer conductor of which is joined to the first element of the pair at approximately the midpoint of the first element and having its center conductor extending to a predetermined feedpoint on the second element, this predetermined point being that at which the center conductor will be substantially impedance matched with the antenna; and, wherein the spacing of the gap between the adjacent ends of the first and second elements is such that the elements are fed by the feedpoint across the gap to provide a matched output of the pair of elements having the desired beam tilt.This application relates to radio wave transmission and reception antennas.