Abstract: A module having a microwave circuit carrier with ribbon conductors for both the fifty ohm transmission line and ground connections. The carrier has a platform raised from the floor of the carrier at the outside interfacing edges. A ribbon conductor is welded between the raised lips on abutting carriers to form a uniform ground plane accessible to top assembly. A second ribbon is welded between RF conductors on substrates in the respective carriers and spans over the interface and the ribbon ground plane. By proper choice of ribbon conductor widths and the spanning height above the ground plane, a fifty ohm impedance can be maintained.