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Maria Sabrina Sarto

Bio: Maria Sabrina Sarto is an academic researcher from Sapienza University of Rome. The author has contributed to research in topics: Electromagnetic shielding & Graphene. The author has an hindex of 34, co-authored 216 publications receiving 4066 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors investigate the use of equivalent-layer models for the analysis of carbon-fiber composite materials and compare results of the reflection coefficient and shielding effectiveness obtained from these effective-property models to results obtained from a full numerical solution based on the actual periodic fiber composite.
Abstract: The purpose of this paper is to investigate the use of equivalent-layer models for the analysis of carbon-fiber composite materials. In this paper, we present three different models for the electromagnetic characterization (effective material properties) of fiber composites that are commonly used in aircraft and EMC/EMI shielding materials. These three models represent various orders (or levels) of detail in the fiber composite structure and, hence, capture various physical aspects of the composite. These models can be used to efficiently calculate the reflection and transmission coefficients, as well as the shielding effectiveness, of these fiber composites. We compare results of the reflection coefficient and shielding effectiveness obtained from these effective-property models to results obtained from a full numerical solution based on the finite-element (FE) method of the actual periodic fiber composite. We show that, as expected, as more of the geometric detail of the fiber composite is captured with the different models, the upper frequency limit of validity increases.

186 citations

Journal ArticleDOI
TL;DR: In this article, the per-unit-length (p.u.l.) equivalent quantum capacitance and kinetic inductance of a multi-wall carbon nanotube (MWCNT) interconnect were derived analytically from the rigorous formulation of the complex multiconductor transmission-line propagation equations.
Abstract: The equivalent single-conductor model of a multiwall carbon nanotube (MWCNT) interconnect is derived analytically from the rigorous formulation of the complex multiconductor transmission-line propagation equations. The expressions of the per-unit-length (p.u.l.) equivalent quantum capacitance and kinetic inductance are obtained in closed form. A new accurate approximated expression of the equivalent p.u.l. quantum capacitance is proposed. It is demonstrated, through analytical derivations and numerical calculations, that the new expression is valid for the most of MWCNT interconnect configurations, whereas a more simplified formula, obtained on the basis of qualitative considerations, produces high approximation errors. The proposed model is solved in both the frequency and time domains. Transient analyses are performed in order to predict the attenuation and time delay of a pulse signal transmitted along an MWCNT as a function of the tube length and number of shells. Simulation results are also compared with measured data available in literature.

173 citations

Journal ArticleDOI
TL;DR: In this article, multiphase composite materials filled with multiwall carbon nanotubes (MWCNTs), short nickel-coated carbon fibers and millimeter-long carbon fibers with various weight fractions and compositions are developed and used for the design of wide-band thin radar-absorbing screens.

155 citations

Journal ArticleDOI
16 Dec 2016-Sensors
TL;DR: The fabrication process and properties of new polydimethylsiloxane (PDMS) foams loaded with multilayer graphene nanoplatelets (MLGs) for application as high sensitive piezoresistive pressure sensors are described and the new graphene-PDMS composite foam is a lightweight cost-effective material.
Abstract: The demand for high performance multifunctional wearable devices is more and more pushing towards the development of novel low-cost, soft and flexible sensors with high sensitivity. In the present work, we describe the fabrication process and the properties of new polydimethylsiloxane (PDMS) foams loaded with multilayer graphene nanoplatelets (MLGs) for application as high sensitive piezoresistive pressure sensors. The effective DC conductivity of the produced foams is measured as a function of MLG loading. The piezoresistive response of the MLG-PDMS foam-based sensor at different strain rates is assessed through quasi-static pressure tests. The results of the experimental investigations demonstrated that sensor loaded with 0.96 wt.% of MLGs is characterized by a highly repeatable pressure-dependent conductance after a few stabilization cycles and it is suitable for detecting compressive stresses as low as 10 kPa, with a sensitivity of 0.23 kPa−1, corresponding to an applied pressure of 70 kPa. Moreover, it is estimated that the sensor is able to detect pressure variations of ~1 Pa. Therefore, the new graphene-PDMS composite foam is a lightweight cost-effective material, suitable for sensing applications in the subtle or low and medium pressure ranges.

150 citations

Journal ArticleDOI
TL;DR: In this paper, a comparative analysis of the electromagnetic properties of new composite materials that are of interest to future aircraft/aerospace structures is presented, and the fabrication process of single-phase and new multiphase micro/nanocomposites is described.
Abstract: This paper presents a comparative analysis of the electromagnetic properties of new composite materials that are of interest to future aircraft/aerospace structures. The fabrication process of single-phase and new multiphase micro/nanocomposites is described. Carbon black, carbon fibers, and multiwall carbon nanotubes are randomly mixed into an epoxy resin matrix at various weight fractions and compositions. The experimental characterization in the frequency range 8-18 GHz shows that the dispersion characteristics of short-carbon-fiber-reinforced composites can be properly controlled by the addition of nanopowders and nanotubes into the mixture. Numerical simulations demonstrate the feasibility of the fabricated materials for the design of new electromagnetic micro/nanostructured shields and radar-absorbing laminates. Thin dielectric Salisbury screens are especially designed to exhibit minimum reflection coefficient at 15 GHz. It shows that the total thickness of the screen can be reduced below 2 mm by using a lossy sheet made of three-phase composites.

143 citations


Cited by
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Journal ArticleDOI
09 Sep 2016-Science
TL;DR: The mechanical flexibility and easy coating capability offered by MXenes and their composites enable them to shield surfaces of any shape while providing high EMI shielding efficiency.
Abstract: Materials with good flexibility and high conductivity that can provide electromagnetic interference (EMI) shielding with minimal thickness are highly desirable, especially if they can be easily processed into films. Two-dimensional metal carbides and nitrides, known as MXenes, combine metallic conductivity and hydrophilic surfaces. Here, we demonstrate the potential of several MXenes and their polymer composites for EMI shielding. A 45-micrometer-thick Ti3C2Tx film exhibited EMI shielding effectiveness of 92 decibels (>50 decibels for a 2.5-micrometer film), which is the highest among synthetic materials of comparable thickness produced to date. This performance originates from the excellent electrical conductivity of Ti3C2Tx films (4600 Siemens per centimeter) and multiple internal reflections from Ti3C2Tx flakes in free-standing films. The mechanical flexibility and easy coating capability offered by MXenes and their composites enable them to shield surfaces of any shape while providing high EMI shielding efficiency.

3,251 citations

Proceedings Article
01 Jan 1999
TL;DR: In this paper, the authors describe photonic crystals as the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures, and the interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.
Abstract: The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

2,722 citations

01 Jan 2017
TL;DR: The 2017 roadmap of terahertz frequency electromagnetic radiation (100 GHz-30 THz) as mentioned in this paper provides a snapshot of the present state of THz science and technology in 2017, and provides an opinion on the challenges and opportunities that the future holds.
Abstract: Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz–30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to 'real world' applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.

690 citations