1. An antenna assembly comprising:a plurality of RF card assemblies, each of the RF card assemblies comprising an RF circuit board having a number of antenna elements;
a backplane circuit board having a top surface with at least one set of power supply rails, wherein each set of power supply rails includes an electric power rail and a ground path rail, wherein the electric power rail comprises a plurality of first connections configured to supply electric power to the RF card assemblies and the ground path rail comprises a plurality of second connections configured to provide a ground path to the RF card assemblies;
a plurality of connectors arranged in rows along the top surface of the backplane circuit board, each of the connectors having a bottom surface configured to engage the top surface of the backplane circuit board, each of the connectors having an inlet configured to receive one of the RF card assemblies along a plane perpendicular to the top surface of the backplane circuit board, wherein the bottom surface includes a plurality of power supply pins configured to engage the electric power rail and the ground path rail; and
a chassis configured to enclose the backplane circuit board, the RF card assemblies, and the connectors;
wherein the RF card assemblies are each spaced a distance apart, wherein the distance is a value corresponding to at least a half wavelength of a highest operating frequency of the antenna assembly.