A millimeter wave transceiver including a plate forming an interposer having its upper surface supporting an interconnection network and having its lower surface intended to be assembled on a printed circuit board by bumps; an integrated circuit chip assembled on the upper surface of the interposer; antennas made of tracks formed on the upper surface of the interposer; and reflectors on the upper surface of the printed circuit board in front of each of the antennas, the effective distance between each antenna and the reflector plate being on the order of one quarter of the wavelength, taking into account the dielectric constants of the interposed materials.