Wide bandwidth flat panel antenna array

A cavity-backed wideband slimline flat panel antenna array for providing a steerable beam includes an array of slot antennas, each of which fed by its own individual dipole radiator, with the wide bandwidth being due to the matching impedances of the slot antenna and dipole radiator across the entire frequency band. In one embodiment an upstanding printed circuit balun feed is connected to each dipole. The dipole elements are located to either side of a slot and are arrayed on the underneath side of a dielectric layer under the substrate into which the slots are formed, with the dipole elements directly fed by individual upstanding printed circuit baluns which are arrayed beneath the individual slots antennas. The use of the dipole elements, in addition to providing a wider operational bandwidth, also permits feeding each of the slots without having to use striplines which would have to cross each other and therefore not work. A wide bandwidth steerable flat panel array utilizing the dipole fed slot antennas may be mounted on the deck house or other flat structural component of a vessel so as to perform a "smart skin" function in which the antenna not only functions as a radiating element but also as a structural part of the vessel itself. In commercial applications, the flat panel array may be incorporated into the wall of a building such that point-to-point communications between buildings may be accomplished through an antenna which is also a structural part of the building. Note that the beams from the antenna are aimable by appropriately phasing the array to point at a receiving antenna on an adjacent building.