US Patent 9698479 Two-dimensionally electronically-steerable artificial impedance surface antenna

A method and apparatus for electronically steering an antenna system. The apparatus comprises a dielectric substrate, a plurality of radiating spokes, and a number of surface wave feeds. The plurality of radiating spokes is arranged radially with respect to a center point of the dielectric substrate. Each radiating spoke in the plurality of radiating spokes forms a surface wave channel configured to constrain a path of a surface wave. Each of the number of surface wave feeds couples at least one corresponding radiating spoke in the plurality of radiating spokes to a transmission line that carries a radio frequency signal.