Novel techniques for packaging and interconnects in MM-wave communication front-ends

Modern MM-wave systems, e.g. for local area networks (LANs), tie lines to mobile communication base stations, or mobile MM-wave communication systems (micro cell communication), require high performance but low cost production. To this end, a combination of planar transmission line circuits (coplanar or microstrip lines, MICs and MMICs) with metal waveguide for low-loss filters and diplexers has to be designed, fabricated, assembled, and packaged effectively. After a short review of some general problems and techniques with respect to interconnects and packaging for MM-wavefront-ends, achievements of a research program in Germany are presented, mainly for the example of components in a 28 GHz communication front-end. This includes the investigation of conventional interconnect techniques, a novel feed-through structure using multilayer carrier substrates for MM-wave circuits, new results in electromagnetic field coupling for interconnects to MM-wave MMICs, and the realisation of packages including waveguide components like filters and diplexers by plastic injection moulding and electroplating.