A U-Band Rectangular Waveguide-to-Coplanar Waveguide Transition Using Metal Ridge

This paper presents a rectangular waveguide-to-coplanar waveguide (CPW) transition using metal ridge at U-band (40-60 GHz). By using an in-house printed circuit board (PCB) technology, a CPW with gap terminations is designed on a Rogers 6002 substrate and its performance is compared with a conventional CPW. As the critical part of the transition, a metal ridge is realized inside the rectangular waveguide and applied to the CPW from top forming an orthogonal structure. The proposed rectangular waveguide-to-CPW transition using metal ridge is designed, fabricated, and measured in a back-to-back configuration. The return loss remains better than 12 dB at U-band with an associated insertion loss of 2.6 dB. Thus, each fabricated transition introduces less than 1.3 dB insertion loss.