Physics-Based Analytical Engineering Models of Graphene Micro- and Nanostrip Lines

In this article, new approximate analytical models of graphene-based micro- and nanostrip transmission lines are given. These models are based on the representation of the mentioned lines by a parallel-plate waveguide embedded into an effective frequency-dependent permittivity media. Our theory allows analytical calculation of complex propagation constant and characteristic impedance of the main quasi-TM mode of graphene strip transmission lines. The developed approach is verified by comparisons with the thin-film lossy microstrips, for which the measurements and theory are available for frequencies up to 1 THz and with parallel-plate graphene waveguides. For very narrow lines, the developed model is improved by a correction tuning technique. The obtained analytical formulas for complex propagation constant and characteristic impedance are interesting in calculations of electronically controlled graphene-based interconnects, microwave and millimeter-wave attenuators, antennas, and transistors.