Sharif Digital Repository

We demonstrate that graphene ribbons can be modeled as circuit elements, which have dual capacitive-inductive nature. In the subwavelength regime, the surface current density on a single graphene ribbon subject to an incident p-polarized plane wave is derived analytically and then it is extended to coplanar arrays of graphene ribbons by applying perturbation theory. It is demonstrated that even isolated graphene ribbons have capacitive properties and the interaction between them in an array only changes the capacitance. Finally, we propose an accurate circuit model for the ribbon array by applying appropriate boundary conditions  

In this paper, an analytical circuit model is proposed for 2-D arrays of graphene disks. First, we derive an analytical expression for the surface current density on a single graphene disk in the subwavelength regime, induced by a normally incident plane wave. The solution is then extended to 2-D arrays of graphene disks using perturbation theory. Finally, by applying appropriate boundary conditions, an R - L - C equivalent circuit of the structure is obtained. It is shown that both a single graphene disk and periodic array of graphene disks have dual capacitive-inductive nature. The results of the proposed model are in excellent agreement with those obtained by full-wave simulations  

The scattering of graphene surface plasmons from an arbitrary, one-dimensional discontinuity in graphene surface conductivity is treated analytically by an exact solution of the quasi-static integral equation for surface current density in the spectral domain. It is found that the reflection and transmission coefficients are not governed by the Fresnel formulas obtained by means of the effective medium approach. Furthermore, the reflection coefficient generally exhibits an anomalous reflection phase, which has so far only been reported for the particular case of reflection from abrupt edges. This anomalous phase becomes frequency-independent in the regime where the effect of inter-band... 

Graphene-based gratings and metagratings have attracted great interest in the last few years because they could realize various multi-functional beam manipulation, such as beam splitting, focusing, and anomalous reflection in the terahertz (THz) regime. However, most of graphene-based metagratings are designed through numerical simulations, which are very time-consuming. In this paper, an accurate analytical method is proposed for diffraction analysis of a perfect electric conductor (PEC)-backed array of graphene ribbons. In contrast to previous analytical treatments, the proposed method can predict the electromagnetic performance of graphene ribbons not only in the subwavelength regime, but... 

Numerical modeling of periodically patterned graphene sheets (PPGS) embedded in planar multilayered media using Fourier-based methods suffers from very slow convergence because of the fact that the conductivity is zero in unfilled areas of the patterned surface and, thus, the so-called Li's inverse rule is not applicable. In this paper, a simple and efficient approach is proposed to overcome this problem such that the exact boundary condition can be applied and the surface current density on PPGS can be obtained accurately. Here, the PPGS is modeled as a conductive surface and only its conductivity representation by the Fourier series is modified. The proposed method can be used easily for...