In this paper, efficient analysis of the plane wave scattering by periodic arrays of magnetically-biased graphene strips (PAMGS) is performed using the semi-numerical, semi-analytical method of lines (MoL). In MoL, all but one independent variable is discretized to reduce a system of partial differential equations to a system of ordinary differential equations. Since the solution in one coordinate direction is obtained analytically, this method is time effective with a fast convergence rate. In the case of a multi-layered PAMGS, the governing equations of the problem are discretized concerning periodic boundary conditions (PBCs) in the transverse direction. The reflection coefficient transformation approach is then used to obtain an analyti

In this paper, graphene-coated spherical nanoparticles are arranged around an infinite length dielectric cylinder to enhance its extinction cross-section. Initially, a single longitudinal one-dimensional periodic array is considered in different loci concerning the transverse electric (TE) incident plane wave. It is observed that regardless of the position of the particles, the extinction cross-section of the dielectric cylinder is considerably enhanced with respect to the bare one. Later, by increasing the number of longitudinal plasmonic arrays around the cylinder, each residing in a different azimuthal direction, the extinction cross-section is further manipulated to observe double pronounced Fano resonances. The origin of the Fano reson

In this paper, dyadic Green's function for a graphene-dielectric stack is formulated based on the scattering superposition method. To this end, scattering Green's function in each layer is expanded in terms of cylindrical vector wave functions with unknown coefficients. Using the Kronecker delta function in the field expansion, it is considered that the field and source points lie in the arbitrary layers. Afterward, recurrence relations for calculating the unknown expansion coefficients are derived by applying the impedance boundary conditions at the interface of a graphene sheet surrounded by two adjacent dielectric layers. The verification of the calculated coefficients is conducted by utilizing them in the analysis of graphene-based stru

In this paper, dyadic Green's function for a graphene-dielectric stack is formulated based on the scattering superposition method. To this end, scattering Green's function in each layer is expanded in terms of cylindrical vector wave functions with unknown coefficients. Using the Kronecker delta function in the field expansion, it is considered that the field and source points lie in the arbitrary layers. Afterward, recurrence relations for calculating the unknown expansion coefficients are derived by applying the impedance boundary conditions at the interface of a graphene sheet surrounded by two adjacent dielectric layers. The verification of the calculated coefficients is conducted by utilizing them in the analysis of graphene-based stru

This paper presents a dual-polarized and dual-frequency reflectarray backed by a frequency selective surface (FSS) with application to shared aperture Ku/Ka-band satellite communication antennas. The reflectarray has been designed to operate simultaneously at 20 and 30 GHz (downlink and uplink frequencies in Ka-band) using a single-layer configuration, where the printed elements are etched on the upper substrate of a two-layer tri-band FSS. The FSS has been designed to be transmissive at 12 GHz (downlink frequency in Ku-band) and reflective at 20 and 30 GHz. An prototype has been fabricated and tested, showing a good matching with the simulations. The measured gains are 28.5 dBi at 20 GHz and 32.25 dBi at 30 GHz.

This paper proposes the phenomenon of extraordinary optical transmission via a magneto-plasmonic nanostructure, which combines magnetic and plasmonic functionalities. The structure includes an active magnetic film magnetized perpendicular to its surface and a plasmonic metal film, perforated with subwavelength circular annular arrays, with a ring placed in the middle of each annular circle. We use the finite element method and the finite-difference time-domain method for simulation of the structure. Numerical analysis shows an improvement in the Faraday rotation and optical transmission, simultaneously, in a magneto-plasmonic structure based on a silver- and bismuth-substituted ferrite garnet. Simultaneous improvement is achieved by couplin

In this paper, we have proposed effective gradient refractive index structures at terahertz frequencies, which function as a planar lens, focusing reflector, and a generalized Luneburg lens (GLL). We base the structures on planar and cylindrical graphene-dielectric multilayer metamaterials. The structures are designed by tailoring the surface conductivity of the graphene layers to provide a given phase profile along with the structures. Therefore, the customizable focus area of the focusing devices, and the tunable terahertz jet effect that is produced by the GLL result. The proposed structures have potential applications in terahertz imaging, sensing, detecting, and communication areas.

A novel dual-polarization, single-layer reflectarray has been designed and manufactured to operate at receive (20 GHz) and transmit (30 GHz) frequencies for Ka-band terminal antennas. The reflectarray unit cell is composed of several types of resonant elements printed on the upper side of a conductor-backed substrate, which are designed to produce a collimated beam at 20 and 30 GHz in dual polarization. Cross-shaped loops are used to provide the required phases at 20 GHz, while crossed dipoles and modified truncated rings are used to control the phasing at 30 GHz. The resonant lengths of the proposed elements have been adjusted cell by cell by means of a two-dimensional interpolation method to achieve the required phase shift at each freque