Abstract: The paper presents the effect of conductive or lossy silicon (Si) substrates on the frequency-dependent distributed series impedance transmission line (TL) parameters, R(ω) and L(ω). The frequency variations of these parameters of the microstrip line for four different conductivities of Si substrate are observed and compared. Keysight Technologies (formerly Agilent’s Electronic Measurement Group) Advanced Design System is used for the electromagnetic simulations of the microstrip line structures. Scattering parameters (S-parameters) based equations are used to plot the variations of series impedance parameters as a function of frequency. Furthermore, this paper explains a complete method to extract various parameters related to a TL. The work extracts the parameters of a microstrip TL model provided with the GlobalFoundries 0.13 μm SiGe BiCMOS8HP process design kit up to 100 GHz.