Smart Graphene-Based Frequency Selective Surface Designed to Act as Single or Dual Band Device with Reconfigurable Operation Bands

Abstract

In this paper, a finite-difference time-domain (FDTD) formulation, based on the exponential matrix and on thin material sheet methods is developed for modeling subcellular thin graphene sheets. This formulation is validated by reproducing graphene frequency selective surfaces (FSS) known from literature. Then, we propose in this work a smart graphene FSS device. Smartness is obtained by means of a unity cell formed by a graphene ring with a graphene sheet placed in its aperture. By properly regulating the chemical potentials of the graphene elements, two frequencytunable modus operandi are obtained: single-or dual-band rejection modes. When the device operates in its dual-band rejection mode, either of the rejection bands can be shifted individually in the frequency spectrum. Additionally, both rejection bands can also be reconfigured simultaneously.

Inertially Controlled Two-Dimensional Phased Arrays by Exploiting Artificial Neural Networks and Ultra-Low-Power AI-Based Microcontrollers

“…The generic element at position (n,m) is excited by means of a signal with amplitude an,m and phase φn,m. The related well-known formula of the Array Factor AF is given in (1), where ψ1 and ψ2 are expressed in ( 2) and ( 3) respectively, with respect to the distance d between two generic elements, to the wave number β=2/, the zenith angle ϴ varying in the interval [0,] and the azimuthal angle  varying in the interval [0,2).…”

“…In this scenario, there is a strong and massive need for efficient algorithms and edge-computing methods to enhance the communication systems by controlling phased arrays radiation patterns, particularly in some high-mobility applications, such as those related to unmanned aerial vehicles (UAVs) -where a communication link with ground control stable over time and regardless of orientation is mandatory-rather than to 5G and automotive -where the reconfigurability time is a crucial parameter. Some works focus on specific material and chemical properties to obtain smart electronic devices, such as the use of graphene to have frequency selective surfaces [1]. Furthermore, other works relate to electronically controlled antennas with the aim of optimizing the radiation pattern without moving the radiators.…”