Coplanar-PGL Transitions on High Resistivity Silicon Substrate in the 57-64 GHz Band and Influence of the Probe Station on the Performances

Abstract : We present Coplanar-Planar Goubau Line (PGL) transitions designed on high-resistivity Silicon to characterize a PGL using microwave probing. These transitions are optimized in the 57-64 GHz frequency band to present excellent electrical performances despite the field disturbance of the measurement setup. As the transitions are positioned on a probe station chuck, a glass substrate is added between the transition under test and the metallic chuck to minimize the disturbance. 3-D full-wave electromagnetic field simulations performed on a commercial software and on-wafer measurements show almost comparable results in term of scattering matrix parameters. Low losses are attained with a measured average transmission parameter of 2.5 dB at 60 GHz for a length of 8 mm of a back-to-back structure with the transitions at the extremities. The measured average insertion loss and return loss per transition are better than 1.36 dB and 11 dB, respectively, with a bandwidth greater than 7% at 60 GHz for a length of 1 mm (about a half of the wavelength at 60 GHz).