Abstract: Wire and Ribbon bonding have been widely used for interconnect of millimeter-wave multi-chip module(MCM). In this paper, characterizations of single, double, triple bondwires and ribbon bonding are discussed in a frequency range from 20 to 40 GHz. The measured results show that the double and triple bondwires are prior to ribbon bonding and ribbon bonding are prior to single bondwire in terms of microwave characterizations.