Electromagnetic wave absorption and structural properties of wide-band absorber made of graphene-printed glass-fibre composite

Lightweight composites combining electromagnetic wave absorption and excellent mechanical properties are required in spacecraft and aircraft. A one- dimensional metamaterial absorber consisting of a stack of glass fibre/epoxy layers and graphene nanoplatelets/epoxy films was proposed and fabricated through a facile air-spraying based printing technology and a liquid resin infusion method. The production process allows an optimum dispersion of graphene nanoplatelets, promoting adhesion and mechanical integration of the glass fibre/epoxy layers with the graphene nanoplatelets/epoxy films. According to experimental results, the proposed wide-band absorber provides a reflection coefficient lower than −10 dB in the range 8.5–16.7 GHz and an improvement of flexural modulus of more than 15%, with a total thickness of ∼1 mm. Outstanding electromagnetic wave absorption and mechanical performance make the proposed absorber more competitive in aeronautical and aerospace applications

Complex Permittivity Extraction Method of a Thin Coating: Em Properties of a Graphene- Based Film on a Composite Layer

In the design of innovative nanomaterials for electromagnetic (EM) field absorption and shielding a crucial issue is the experimental characterization of the complex effective permittivity of non-uniform layered materials or electrically thin lossy layers. This paper proposes a technique to retrieve the complex relative permittivity of a thin lossy coating supported by a dielectric substrate through transmission/reflection measurements in a rectangular waveguide. A 2-port network de-embedding method is applied to remove the EM contribution of the substrate, and the so obtained scattering parameters of the film are used in the modified Nicolson- Ross-Weir algorithm to extract the complex permittivity. The method, validated by simulations, is applied to characterize a glass-fiber reinforced composite coated with a thin coating made of graphene nanoplatelets (GNPs)-polymer composite. Finally, the reflection properties of radar absorbing panels, constituted by several bilayers of GNP-coated GFRC are investigated in the range 12.4-18 GHz

Broadband electromagnetic absorbing structures made of graphene/glass-fiber/epoxy composite

Radar-absorbing structures (RASs) with improved mechanical properties and subwavelength thickness are of particular interest for aerospace applications and electromagnetic (EM) interference control. This article proposes a new RAS, made of a graphene-filled lossy laminate (LL) with impedance adapter, having a total thickness less than 4 mm and a normalized absorption bandwidth of 84% in the frequency range 6-18 GHz. The RAS is designed by applying an innovative simulation approach of the graphene-filled LL, which is based on the multiscale Maxwell Garnett model and the effective medium theory. Experimental tests are performed in order to validate the developed model and to assess the absorption properties of the produced RAS, having a minimum reflection of -30 dB and an absorption bandwidth at -10 dB of 10 GHz, with a central frequency of 12 GHz and a graphene nanoplatelets concentration less than 5 g/m

A forward silicon strip system for the ATLAS HL-LHC upgrade

In the year 2022 an upgrade of the Large Hadron Collider (LHC) is planned to increase the luminosity such that an integrated luminosity of View the MathML sourceLint∼3000fb−1 can be accumulated by 2030 [1]. The radiation damage of the present inner tracker at this date and the high track density of the High Luminosity LHC (HL-LHC) require an upgrade of the inner tracker of the ATLAS (A Toroidal LHC ApparatuS) experiment. A new integration concept will be used: the readout electronics is directly glued on the strip surface of the silicon sensors and the sensors are glued to a support structure. For the barrel region this structure is referred to as a Stave and for the end-cap region it is referred to as a Petal. For tests a smaller version, the Petalet, will be build with two design concepts. In this article the construction method is explained and first hybrid test results for one Petalet sensor are presented