In this paper, conductive losses of multi-chip module interconnections are analysed. A distributed network model for the conductor surface impedance is extended to include the transition from DC resistivity to high frequency losses and to cover the effect of barrier and adhesion layers. Using this model, a broadband loss expression is derived. This loss expression can be implemented in network simulators for transient analysis of lossy interconnections. The validity and applicability of the model is experimentally verified by comparison with measured S-parameters. Measurements extend from 45 MHz to 18 GHz. They are performed on test structures realised with two different MCM-D technologies. Excellent correspondence between measurements and simulations is achieved, even when magnetic effects of a thick nickel barrier layer are involved. The models are incorporated in the transient analysis network simulation program Transplus. Several simulation examples using Transplus are shown.