Circularly polarized radio frequency antenna

A radio frequency antenna comprising:

• (a) a waveguide section comprising a pair of opposing, relatively wide walls and a pair of opposing, relatively narrow side walls;
• (b) first means, disposed in the waveguide section, for establishing radio frequency energy in such waveguide section having a first linear polarization with an electric field disposed normal to the opposing wide walls of the waveguide section;
• and
• (c) second means, for establishing radio frequency energy having a second linear polarization with an electric field disposed perpendicular to the electric field of the first linear polarization, such second means comprising a microwave circuit including a strip conductor feed separated from a ground plane conductor by a dielectric, said second means being disposed within the waveguide section between the pair of opposing wide walls and relative to the first means to provide the radio frequency energy having the first linear polarization and the radio frequency energy having the second linear polarization with substantially coincident phase centers, said ground plane conductor being dielectrically spaced from the pair of opposing, relatively narrow side walls.

In combination:

• means for producing a pair of quadrature radio frequency signals;
• and
• radio frequency antenna means, responsive to the pair of quadrature radio frequency signals, for producing circularly polarized radio frequency energy, said radio frequency antenna means comprising:
• (i) electrically conductive waveguide means comprising a pair of opposing, relatively wide walls;
• (ii) feed means, resonsive to a first one of the pair of quadrature radio frequency signals, for establishing radio frequency energy in the waveguide means having a first linear polarization with an electric field disposed normal to the opposing wide walls of the waveguide means;
• and
• (iii) planar microwave circuit means, comprising a strip conductor feed separated from a ground plane conductor by a dielectric and fed by a second one of the pair of quadrature radio frequency signals, for establishing radio frequency energy having a second linear polarization with an electric field disposed perpendicular to the electric field of the first linear polarization, said microwave circuit means being disposed intermediate the pair of opposing, relatively wide walls with said ground plane conductor being dielectrically spaced from the waveguide means, said waveguide means producing circularly polarized radio frequency energy from the first linear polarization and the second linear polarization.