A packaged electronic device includes a multilayer lead frame having first and second trace levels, a via level therebetween, a conductive feed structure, and a conductive reflector wall. The first trace level includes a conductive coupler antenna and a conductive ground structure that extends in a plane of orthogonal first and second directions, and a portion of the conductive coupler antenna faces outward along a third direction orthogonal to the first and second directions. The conductive reflector wall has an opening and extends along the third direction between the first and second trace levels around a portion of the conductive coupler antenna. The conductive feed structure is coupled to the conductive coupler antenna and extends along the first direction through the opening of the conductive reflector wall.