Analysis and Equivalent Circuit of Anisotropic Graphene Metasurfaces

Abstract

The equivalent circuit representation of metasurfaces (MTs) is a powerful approach for both designing and physically under- standing these two-dimensional devices. This paper presents an equivalent circuit representation for anisotropic graphene patch (AGP) and anisotropic complementary graphene patch (ACGP) MTs. This representation allows us to readily extract the characteristics of surface plasmon polariton (SPP) wave propagation along these MTs. A key fnding is that AGP MTs, unlike isotropic graphene patch (IGP) MTs, support the simultaneous propagation of both SPP transverse magnetic (TM) and SPP transverse electric (TE) mode waves, opening possibilities for designing diverse graphene-based devices. Using a transmission- line approach, we frst examine the diagonal impedance matrix of anisotropic graphene (AG) MTs when the propagation direction aligns with a principal axis of MTs. Next, we derive the dispersion equation using the transverse resonance tech- nique. Finally, we extend this model to calculate the full impedance matrix of AG MTs for arbitrary propagation directions. The equivalent circuit model and simulated results demonstrate good agreement and validate the proposed equivalent circuit.