A millimeter-wave wide-band transition from a differential microstrip to a rectangular waveguide for 60 GHz applications

In this paper an integrated wide-band transition from a differential micro-strip line to a rectangular WR-15 waveguide is presented. The transition makes use of a cavity that is entirely integrated into the multilayer printed circuit board (PCB), which offers three layers (RF signal layer, ground plane and DC signal layer) for signal routing. The transition including the 18 mm long micro-strip feed lines provides a bandwidth of 20 GHz from 50 GHz to 70 GHz and an insertion loss of less than 2.3 dB. This makes the transition perfectly suited for differential wide-band transceivers operating in the 60 GHz band.