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An antenna system for an array antenna includes an array of radiators formed as patch antenna elements on a dielectric substrate, there being a shielding metallic sheet on a side of the substrate opposite the radiators. A further dielectric substrate and a bottom metallic sheet are disposed on a sid

An antenna system for an array antenna includes an array of radiators formed as patch antenna elements on a dielectric substrate, there being a shielding metallic sheet on a side of the substrate opposite the radiators. A further dielectric substrate and a bottom metallic sheet are disposed on a side of the shielding sheet opposite the radiators. An antenna feed system is disposed in the further sheet. Coupling devices such as orthogonal slots, in one embodiment, or a microwave crossover in a second embodiment, couple electromagnetic power from the feed system to the radiators through the shielding sheet. In the case of the coupling slots, the feed system provides phase quadrature signals for development of circularly polarized radiation. The crossover provides only a linearly polarized wave, and is formed of two coplanar waveguides, one in the shielding sheet and one in the bottom sheet. Each of the coplanar waveguides includes a pair of coupling pads, the pads of one waveguide being in registration with the pads of the other waveguide.

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An antenna system comprising: a first electrically-conductive sheet; a second electrically-conductive sheet; means for supporting said second sheet parallel to said first sheet and spaced apart therefrom; an array of radiators; means for positioning said array of radiators in spaced-apart relation f

An antenna system comprising: a first electrically-conductive sheet; a second electrically-conductive sheet; means for supporting said second sheet parallel to said first sheet and spaced apart therefrom; an array of radiators; means for positioning said array of radiators in spaced-apart relation from said second sheet, said second sheet being located between said radiators and said first sheet; a plurality of crossovers for transferring electromagnetic power from said first sheet to said second sheet, wherein each of said crossovers comprises: a first coplanar transmission line disposed in said first sheet, a first portion of said first transmission line being formed as a first coupling pad and a second portion of said first transmission line being formed as a second coupling pad; a second coplanar transmission line disposed in said second sheet, a first portion of said second transmission line being formed as a third coupling pad and a second portion of said second transmission line being formed as a fourth coupling pad; and wherein each of said transmission lines is a coplanar waveguide formed as a pair of slots within a corresponding conductive sheet, the pair of slots being spaced apart to define a central strip conductor therebetween; a plurality of coupling elements disposed within said second sheet and connected to corresponding ones of said crossovers for coupling electromagnetic power between said corresponding ones of said crossovers and respective ones of said radiators; power distribution means disposed at least in part on said first sheet and connected to each of said crossovers, said second sheet shielding said radiators from said power distribution means; in each of said transmission lines, each of said coupling pads is formed as a widened portion of the central strip conductor, and each slot ha a widened portion contiguous each pad; said first pad is disposed in registration with said third pad and said second pad is disposed in registration with said fourth pad for coupling electromagnetic power between said first and said second transmission lines; each of said pads has a first and a second end, and extends in a longitudinal direction along a corresponding transmission line from the first end of the pad to the second end of the pad, each of said pads has opposed sides extending in the longitudinal direction from the first end of the pad to the second end of the pad, the sides and the ends of said first pad being in registration with the sides and the ends respectively of said third pad, the sides and the ends of said second pad being in registration with the sides and the ends respectively of said fourth pad; an end of said first transmission line extending from said first pad serves as an input pot of said crossover and is connected to said power distribution means; an end of said first transmission line extending from said second pad is terminated in a matched load; an end of said second transmission line extending from said third pad is terminated in a matched load; an end of said second transmission line extending from said fourth pad serves as an output port of said crossover and is connected to a corresponding coupling element for transferring power from said distribution means past said second sheet to a radiator.