Flat phased array antenna

Abstract

A flat phased array antenna for reception of circularly polarized high frequency signals. The flat antenna array consists of a number of subarrays arranged in a matrix. In turn, each of the subarrays consist of individual antenna elements arranged in a matrix. In one embodiment, each subarray consists of four layers stacked one on top of the other. The top layer defines an array of miniature reception horns. Secured to the top layer is a second layer which constitutes the short-circuit plate of the antenna array. The short-circuit plate contains a plurality of through holes disposed about the surface of the circuit plate to permit passage of pairs of cylindrically shaped probes. The two remaining layers constitute the first power dividing layer and the second power dividing layer, respectively. Each of the layers includes transmission line waveguides. The complete interior surface of the waveguides is coated with a metallic film and contains a number of spaced non-conductive supports for supporting a metallic conductor at the central location of the waveguide when the channel is viewed in cross-section. This arrangement creates a rectangular coaxial transmission line with the conductor forming the central conductor and the metallically coated channel forming the outer conductor. At the end of certain channels are the vertically extending, cylindrically shaped non-conductive probes. In a second embodiment, non-conductive strips with spaced supports carry the conductor. The probes are intengrally formed as part of the non-conductive strips. In still another embodiment, the probes of the first embodiment are replaced by conductive legs formed in the same plane as the metallic conductor. In addition, the two channels are formed along both sides of a single layer and recessed into that layer.