Integration of passive components for microwave filters in MCM-D

The increasing demand for high density packaging technologies and the evolution to mixed digital and analogue devices has been the on-set of increasing research in microwave thin film multi-layer technologies such as the MCM-D technology. In this technology passive components may be integrated in the substrate and combined to realise more complex microwave functions. In this paper a basic comparison and a process parameter sensitivity analysis is made for the transmission line characteristics of interconnections in single layer MIC technology and in thin film MCM technology. For reasons of better accessibility, enhanced phase velocity and reduced process tolerance susceptibility, coplanar lines on MCM show to be advantageous. However, the multi-layered nature offers alternative possibilities to implement passive components. In this way a coplanar floating patch capacitor is introduced. Other passive components, such as thin film NiCr resistors, high quality spiral and line inductors and other types of capacitors are discussed. These passives have been combined to realise integrated passive filter functions, of which an example is shown.