Array packages and methods for forming large-scale antenna arrays. One method includes aligning two or more array packages. The two or more array packages each include one or more bottom dielectric layers, an array of antennas arranged in a plane above the one or more bottom dielectric layers, a ground plane layer above the one or more bottom dielectric layers, and a conductive surface on at least a part of an outside surface of the array package and orthogonal to the plane of the array of antennas. The conductive surface is electrically connected to the ground plane layer.