Modeling and Analysis of Sub-Millimeter-Wave Graphene Switches for
On-Wafer Coplanar Transmission Lines
Abstract
We present an analysis of graphene loaded transmission line switches.
Namely, we propose equivalent circuit models for graphene loaded
coplanar waveguides and striplines and examine the switching performance
under certain design parameters. As such, the models account for the
distributed effects of electrically-large shunt switches in coplanar
waveguides and we use the Babinet’s principle to derive the respective
models for the coplanar stripline transmission lines. Using these
models, we identify the optimum design of graphene switches based on
transmission line characteristic impedance, scaling factor, graphene
shape, and topology (series or shunt). We vary these parameters and
obtain the insertion loss and ON/OFF ratio. Τhe extracted results can
act as the design roadmap toward an optimum switch topology and
emphasize the limitations with respect to fabrication challenges,
parasitic effects, and radiation losses. In our models, we use measured
graphene values (sheet impedance) instead of theoretical equations, to
obtain the actual switching performance. Finally, the proposed
equivalent models are crucial for this in-depth study; since, we
simulated more than 2,000,000 configurations, a computationally
challenging task with the use of full-wave solvers