A micromachined transmission line for microwave and millimetre-wave ap
plications has been fabricated and characterised in the 20-40 GHz rang
e. Using this topology, the direct integration of both mesa and discre
te devices is possible making the line suitable for MIC and MMIC appli
cations. This structure can also be used as an alternative to preforme
d substrates for millimetre-wave MIC circuits.