The scattering of terahertz radiation on a graphene-based nano-patch antenna is numerically analyzed. The extinction cross section of the nano-antenna supported by silicon and silicon dioxide substrates of dierent thickness are calculated. Scattering resonances in the terahertz band are identied as Fabry-Perot resonances of surface plasmon polaritons supported by the graphene lm. A strong tunability of the antenna resonances via electrostatic bias is numerically demonstrated, opening perspectives to design tunable graphene-based nano-antennas. These antennas are envisaged to enable wireless communications at the nanoscale.

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Abstract-Nanonetworks, the interconnection of nanosystems, are envisaged to greatly expand the applications of nanotechnology in the biomedical, environmental and industrial fields. However, it is still not clear how these nanosystems will communicate among them. This work considers a scenario of Diffusionbased Molecular Communication (DMC), a promising paradigm that has been recently proposed to implement nanonetworks. In a DMC network, transmitters encode information by the emission of molecules which diffuse throughout the medium, eventually reaching the receiver locations. In this scenario, a pulse-based modulation scheme is proposed and two techniques for the detection of the molecular pulses, namely, amplitude detection and energy detection, are compared. In order to evaluate the performance of DMC using both detection schemes, the most important communication metrics in each case are identified. Their analytical expressions are obtained and validated by simulation. Finally, the scalability of the obtained performance evaluation metrics in both detection techniques is compared in order to determine their suitability to particular DMC scenarios. Energy detection is found to be more suitable when the transmission distance constitutes a bottleneck in the performance of the network, whereas amplitude detection will allow achieving a higher transmission rate in the cases where the transmission distance is not a limitation. These results provide interesting insights which may serve designers as a guide to implement future DMC networks.

Nanotechnology is the engineering of functional systems at the molecular/atomic level. Nanomachines are expected to be very simple devices, but nanonetworks, the association of nanomachines, are expected to increase their capabilities, allowing them to share information in order to perform more complex tasks and increase their range of operation. How nanomachines will communicate is currently under In this work, the diffusion-based MC channel is explored in order to extract its main communication metrics, such as attenuation and delay with respect to frequency and distance. The LTI property is proven to be a valid assumption for normal diffusionbased single/multi-transmitter scenarios. Different pulse-based modulation techniques are compared by means of throughput, operation range, energy requirements and ISI, and the optimal pulse shape for these modulations is provided. Finally, interferences are evaluated in a broadcast communication scenario and diffusion-based noise is observed and assessed with reference to already proposed stochastic models.The exploration of the physical diffusion-based communication channel is based on simulations. N3Sim, a simulation framework for the general case of diffusion communication, is presented and used for the simulations.We aim to contribute with this simulator and this study to continue the development of an appropriate channel model tailored to the physical layer singularities of

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Diffusion-based molecular communication is a promising bio-inspired paradigm to implement nanonetworks, i.e., the interconnection of nanomachines. The peculiarities of the physical channel in diffusion-based molecular communication require the development of novel models, architectures and protocols for this new scenario, which need to be validated by simulation. N3Sim is a simulation framework for nanonetworks with transmitter, receiver, and harvester nodes using Diffusion-based Molecular Communication (DMC). In DMC, transmitters encode the information by releasing molecules into the medium, thus varying their local concentration. N3Sim models the movement of these molecules according to Brownian dynamics, and it also takes into account their inertia and the interactions among them. Harvesters collect molecules from the environment to reuse them for later transmissions. Receivers decode the information by sensing the particle concentration in their neighborhood. The benefits of N3Sim are multiple: the validation of channel models for DMC and the evaluation of novel modulation schemes are just a few examples.

Abstract-Nanotechnology is enabling the development of devices in a scale ranging from one to a few hundred nanometers, known as nanomachines. How these nanomachines will communicate is still an open debate. Molecular communication is a promising paradigm that has been proposed to implement nanonetworks, i.e., the interconnection of nanomachines. Recent studies have attempted to model the physical channel of molecular communication, mainly from a communication or information-theoretical point of view. In this work, we focus on the diffusion-based molecular communication, whose physical channel is governed by Fick's laws of diffusion. We characterize the molecular channel following two complementary approaches: first, we obtain the channel impulse response, transfer function and group delay; second, we propose a pulse-based modulation scheme and we obtain analytical expressions for the most relevant performance evaluation metrics, which we also validate by simulation. Finally, we compare the scalability of these metrics with their equivalents in a wireless electromagnetic channel. We consider that these results provide interesting insights which may serve designers as a guide to implement future molecular nanonetworks.

Graphene, owing to its ability to support plasmon polariton waves in the terahertz frequency range, enables the miniaturization and electrical tunability of antennas to allow wireless communications among nanosystems. One of the main challenges in the characterization and demonstration of graphene antennas is finding suitable terahertz sources to feed the antenna. This paper characterizes the performance of a graphene RF plasmonic antenna fed with a photoconductive source. The terahertz source is modeled and, by means of a full-wave EM solver, the radiated power as well as the tunable resonant frequency of the device is estimated with respect to material, laser illumination and antenna geometry parameters. The results show that with this setup, the antenna radiates terahertz pulses with an average power up to 1 µW and shows promising electrical frequency tunability.