Dual polarization antennae

摘要

A dual polarization antenna includes a non-conducting space surrounded by a ground plane. Two angularly offset sets of dipole structures penetrate into the space. Each set of dipole structures comprises a pair of aligned short circuit elongate dipoles extending from the ground plane into the space from diametrically opposed directions and terminating in respective free ends. The free ends are adjacent, but spaced from each other, to define a gap between them. At least one separate device is provided for exciting each set of dipole structures or each dipole structure within a set individually. A radiating element is provided overlying the dipole structures such that the dipole structures couple, in use, with the radiating element, causing the radiating element to radiate polarizations determined by the orientation of each of the sets of dipole structures.