Planar array antenna

Claim 1

A planar array antenna of a series-feed type comprising: a planar grounding conductor; a planar first dielectric substrate having said grounding conductor disposed on one of its surfaces; an elongate feeder line disposed on another surface of said first dielectric substrate to extend from one end to another end of said first dielectric substrate, said feeder line having no branched portion; a planar second dielectric substrate having one of its surfaces disposed adjacent to said feeder line and said other surface of said first dielectric substrate; and a plurality of radiation elements for radiating radio frequency power supplied through said feeder line, said radiation elements being arrayed on another surface of said second dielectric substrate so as to be opposite to said feeder line across said second dielectric substrate, said radiation elements being supplied said radio frequency power starting from an end radiation element positioned nearest to a feeding end of said feeder line, said feeder line having a first feeder part spaced apart by a predetermined distance from a marginal contour of one of said radiation elements in the planar direction of said second dielectric substrate and a second feeder part disposed within a width of a marginal contour of another one of said radiation elements and directly beneath said another radiation element, and said second feeder part being divided into two parts arranged along a longitudinal axis of said feeder line with respective ends thereof confronting each other, a power coupling coefficient between said second feeder part and said another radiation element being selected to be larger than a power coupling coefficient between said first feeder part and said one of said radiation elements.