A structure including a first wafer, including first active components configured so as to introduce a phase shift; a first metal layer, formed on a first surface of the first wafer; a first interconnect structure, formed on a second surface of the first wafer, including first bias lines; a set of first planar antennas, formed on the first interconnect structure; a second wafer; a second metal layer, formed on a first surface of the second wafer; a set of second planar antennas, formed on a second surface of the second wafer; the first and second wafers being joined by way of the first and second metal layers such that the first and second planar antennas are aligned, the first and second metal layers forming a ground plane.