Interconnect structures for integrated microwave and millimetre wave circuits: current status and trends

Applications requiring high frequency IC interconnect range ever more widely: from cellular phones, indeed the entire wireless sector, to millimetre-wave automotive radars. Highly-miniaturised communications and radars require small and compact overall designs with unobtrusive antennas. Operating frequencies extend over many decades of the spectrum: from around 900 MHz to 1 THz (1,000 GHz) for submillimetre-wave technology. The technological capability is generally available now-commercially in the case of microwave and well into the millimetre-wave bands. There are, however, many areas in which leading-edge research is being performed. These include novel designs, the challenges of cost-critical applications, and high millimetre-wave or submillimetre-wave approaches. The possible available technologies range from microstrip to suspended substrate and dielectric waveguide, but the selection of an appropriate technology fix the interconnection of MMICs is a critical decision.