The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Starting from Dirac equation for an idealized graphene layer together with the Lorentz gauge condition, we describe plasmon propagation without making recourse to a classical Kubo-Drude electron model. Two excitation modes are separately considered : 1) excitation by a TM-polarized wave of given vector potential amplitude (voltage source), 2) excitation by current injection (e.g. via a probe)(current...
We report on numerical analysis of opto-mechanical (OM) cavities, with a full description of the rigorous numerical scheme involved, with emphasis on the mechanical stress induced by EM fields. In the future, OM structures are likely to be integrated in planar technology as pumped phonon sources and detectors, as well as phonon processing components (waveguides, splitters, memories) to process information...
In this work, Scanning Microwave Microscopy (SMM) is applied to breast cancer cells MCF-7 treated by fullerene (C60), in order to provide simultaneous topographic and electromagnetic characterization of sample surface. The exceptional properties of fullerene, like its lipophilicity and its ability to be functionalized with proteins and nucleic acids, make its use very promising for drug delivery and...
Graphene transistors are currently the object of deep investigation, both in theoretical and experimental directions. In this contribution, we show self-consistent analysis of graphene based FETs, in a ballistic framework, in order to provide a rigorous tool to improve knowledge of the device behavior down to the nanoscale. Still, many points remain open, and there is a high demand for numerical tools...
Excitation and propagation of surfaces waves in graphene are analyzed within a frequency band of 1 to 300 THz, and a time domain of 1 to 10 ps. An ab initio approach, based on time dependent density functional theory in linear response regime is used. The key outputs of the simulation are the ab-initio conductance in time and frequency. This is shown to tend to a continuous integral relations in graphene,...
In this paper we present a new way of biasing the graphene radiator of a coplanar patch antenna by exploiting an ad-hoc designed backside metallization. Due to the intrinsic physical properties of graphene, this would represent the most effective way to tune antenna matching and radiation characteristics by tuning graphene surface impedance. Simulation results are provided, showing that the proposed...
Excitation and propagation of surfaces waves in graphene and graphene nanoribbons are analyzed, within a frequency band of 1 to 300 THz, based on time dependent density functional theory, in linear response regime. The key outputs of the simulation is the ab-initio complex impeance of the materials. This is shown to tend to a continuous integral relations in graphene, when the valence and conduction...
We report on ab initio and semi-empirical techniques to investigate the electromagnetic response of 2D materials with honeycomb lattice. Band structure simulations, using density functional theory, are performed on pristine graphene and silicene. The predictions on the unique electronic features of these systems are compared to those obtained with some commonly used approaches, based on the tight-binding...
We report on an ab initio technique for modeling the electromagnetic response of graphene in the THz range. Quantum mechanical calculations are performed using linear response density functional theory, and compared with a semi-phenomenological model derived from the Kubo formula. We present a novel concept of dispersive conductivity, which goes beyond the Kubo-Drude model and results in a self-consistent...
In the past decade the progresses in nanofabrication, modeling (from atomistic to mesoscopic scales), and advances in nanocharacterisation have triggered an entirely new class of nanodevices. Owing to their superior electrical and mechanical performances, carbon based meterials such as graphene and carbon nanotubes (CNTs) have played a central role in these groundbreaking developments. Among the many,...
We report on multiphysics full-wave techniques in the frequency (energy)-domain and time-domain, aimed at the investigation of the combined electromagnetic-coherent transport problem in nano-structured materials and devices, in particular carbon-based materials/devices. The quantum transport is modeled by i) discrete Hamiltonians at atomistic scale, ii) Schrödinger equation, and/or Dirac/Dirac-like...
We present the design of a graphene-based electronically tuneable microstrip attenuator operating at a frequency of 5 GHz. The use of graphene as a variable resistor is discussed and the modelling of its electromagnetic properties at microwave frequencies is fully addressed. The design of the graphene-based attenuator is described. The structure integrates a patch of graphene, whose characteristics...
We report on advanced full-wave techniques, both in the frequency and energy domains, aimed at the investigation of the combined electromagnetic-coherent transport problem in pristine graphene, as well as in some 2D-materials beyond graphene, with particular attention to buckleld silicene.
Full-wave multiphysics techniques aimed at the investigation of the combined electromagnetic-coherent transport phenomena in carbon-based nano-structures/devices are presented. Advanced numerical tools, in the frequency (energy)-domain and time-domain and in multi-scale environment are derived. The quantum transport is modeled by i) discrete Hamiltonians at atomistic scale, ii) Schrödinger equation,...
In this work, a novel procedure for the simulation of magnetically-biased graphene by means of standard simulators, is made available. To this aim, the similarity of graphene with lossy ferrite has been exploited. Simulations can be performed at microwave frequency, from DC up to 100 GHz, where the electromagnetic response of graphene is almost flat. The Duality theorem is applied to establish the...
This paper presents the design of a graphene-based electronically tunable microstrip attenuator operating at the frequency of 5 GHz. The use of graphene as a variable resistor is discussed, and the modeling of its electromagnetic properties at microwave frequencies is fully addressed. The design of the graphene-based attenuator is described. The structure integrates a patch of graphene, whose characteristics...
In this contribution, three terminal ballistic junctions, made of three-branch graphene nanoribbons (GNRs), are modeled at the nanometric scale. This configuration is used for the realization of rectifiers, harmonic generator, mixers, switches. The analysis is carried in the frequency (energy) domain by a scattering matrix approach, optimized for GNR devices. The ballisticity and the scattering properties...
In this contribution, the electrostatic tunability of graphene is exploited in order to fabricate compact and effective microwave filters, namely field attenuators. A graphene patch of millimeter size is placed across the air gap of a discontinued microstrip-line, and tuned by means of an electrostatic bias applied by a high impedance line, that is, in turns, de-coupled from the microwave filter at...
We analyze a coplanar graphene-based nano-patch antenna. Besides the fact that graphene is a moderate conductor at those frequencies, the antenna can still exhibit sharp resonances. Although the poor graphene conductivity implies in general low-performance, a remarkable change of the scattering parameters, radiation pattern and antenna efficiency can be observed as the graphene surface impedance is...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.