Abstract: A broadband slot array antenna employs a closely arranged array of slot antennas to minimize antenna size. The antenna array includes a common input terminal; a conductor plate having a common slot formed in a predetermined area and a plurality of slot halves being formed separately and respectively communicating with the common slot via a plurality of slot necks spaced by a predetermined distance; a plurality of feed lines, each having one terminus connected to the common input terminal, for applying power to the conductor plate at a cross coupling point; and a dielectric layer disposed between the conductor plate and the plurality of feed lines.