Planar Goubau line (PGL) structures on high-resistivity silicon are adapted to the 57-64 GHz frequency band. Simulations and measurements show a lower attenuation than with the coplanar line is obtained. Very low losses are attained with a measured average attenuation of 0.064 dB/mm on the whole band. To allow this measurement, coplanar-PGL transitions have been optimized.

Abstract-An inverted micro-strip line (IML) is proposed at microwave and millimeter wave frequencies. This IML on high resistivity silicon (HRS) is studied from 10 to 100 GHz and presents an attenuation lower than 0.08 dB/mm on the whole frequency band. A parametric study, in order to minimize the attenuation and the dispersion of the inverted line in the 10-100 GHz bandwidth, is performed using numerical full wave calculations with HFSS (High Frequency Structural Simulator) tool. A complementary study is added: a large variety of characteristic impedances (for instance, from 38 Ω to 87 Ω at 60 GHz) is performed, the change of propagation modes is observed and the qualification and quantification of the losses allows minimizing them. A comparison with a line of the same length and width without ground plane, the Planar Goubau Line (PGL) is reported in the 10-100 GHz band and a first measure of the PGL is performed, in the 55-67 GHz band, presenting the same propagation mode as the IML at 60 GHz. The measured attenuation of 0.064 dB/mm in the 55-67 GHz obtained for the PGL promises a comparable value for the IML in the measured band.

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 fullwave 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).