An antenna circuit board assembly comprises a substrate having a ground plane comprised of a conductive material; a first antenna element mounted to the substrate and coupled to the ground plane; a second antenna element mounted to the substrate and coupled to the ground plane; a third antenna element mounted to the substrate and coupled to the ground plane; and a plurality of features etched into the ground plane, each of the plurality of features having a respective length and a respective width. The respective length and the respective width of each of the plurality of features are selected to increase isolation between the first, second, and third antenna elements.