A microwave electronic component comprising a substrate having top and bottom substrate surfaces; the substrate comprising an aperture between the top and bottom substrate surfaces; a metallic heat sink filling the aperture; a microwave integrated circuit having a top circuit surface with at least one microwave signal port and a bottom circuit surface in contact with the metallic heat sink; a signal line comprising at least a metallic via between the top and bottom substrate surfaces, and a top signal conductor arranged between the microwave signal port and the metallic via; wherein the dimensions and location of the metallic via are chosen such that the metallic via forms, together with the metallic heat sink, a first impedance-matched non-coaxial transmission line.