A vertical combiner for an overlapping linear phased array is provided. The vertical vector combiner enables two strip-line signals from different layers to be combined, or divided, by vertical transitions between substrate layers and produce a desired output signal phase. The combiner can terminate in a short to act as an antenna. In an antenna application, the antenna provides multiple substrate layers for each strip-line signal, each having a metal ground plane. The ground planes are be coupled by vertical transitions access enabling a stepped ground within the structure which increases bandwidth. The multi-layer combiner architecture enables integration with phased array feed networks for millimeter wave phased array antennas.