Investigation of CMOS on-chip transmission lines CPW, SCPW and CPWG up to 110GHz

On-chip transmission lines are basic components in millimeter-wave and terahertz circuits. As the frequency goes up, the transmission lines are more and more important to determine the performance of the circuits. In this paper, CPW, slow wave CPW (SCPW) with different shielding layers and CPWG fabricated in a commercial 0.18 ¿m CMOS process have been characterized and analyzed. Based on measured two-port S-parameters up to 110 GHz, the attenuation and phase constants are compared. The relative dielectric permittivity is extracted and the relation with the reverse of the distance is shown which provides the hint for the choice of the shielding layers. However, the application frequency should be considered due to the attenuation is strongly frequency dependent.