Papers by Keyword: Metamaterials

Abstract: The integration of infrared nanoantenna technology into architectural design presents a novel approach to enhancing buildings’ energy efficiency by converting ambient electromagnetic radiation, particularly in the infrared spectrum, into usable electrical power. This technology offers significant potential to reduce buildings’ reliance on external power sources, contributing to a more sustainable energy ecosystem. The development of advanced nanotechnology, metamaterials, and responsive coatings is essential for creating adaptive surfaces capable of capturing and utilizing radiant energy. Given the increasing global energy demand and the urgency to combat climate change, infrared nanoantennas represent a promising frontier in renewable energy harvesting. This paper provides a detailed examination of recent advancements in nanoantenna technology, fabrication methods, and integration strategies within building materials. Furthermore, it addresses the practical challenges of implementing these systems in architectural design, offering insights into how this emerging technology could contribute to the development of self-sustaining, energy-efficient structures.

Abstract: In this research the effect of the geometric features of an auxetic metamaterial structure was investigated by the authors. In particular, a re-entrant honeycomb geometry was selected as case study. Connectors inclination, width and length have been changed to study mechanical behavior and deformation under compression. The procedure adopted was both experimental and numerical. Solutions proposed highlight benefits in terms of compression load and controlled lateral displacement that is possible to achieve.

Abstract: Various filling fractions of silver silica nanocomposites (Ag-SiO₂ NC) were successfully synthesized via sol-gel technique and deposited onto indium tin oxide via electrophoretic deposition (EPD). Ag-SiO₂ NC was investigated using X-ray diffraction, FTIR spectroscopy, Uv-vis and transmission electron microscopy. The XRD and Uv-vis results revealed that Ag-SiO₂ NC is stable with a filling fraction of 0.6 in the dielectric medium with excellent absorption peak. Spectroscopy Ellipsometry shows that the effective permittivity and refractive index obtained from this filling fraction are -0.88 and 0.90, respectively. We discovered a ragged of metamaterial properties at negative permittivity.

Abstract: Metamaterials are controlled arrangements of material structures in which their mechanical properties can be tailored by tuning their geometrical parameters. A parametrization based on cubic Bézier curves is employed here to generate cantilever lattice-beams by changing the position of a free control point. The apparent stiffness of these lattice-beams is numerically analyzed by means of tensile, bending, and free vibration simulations. Results expose the influence of shear deformation in the mechanical behavior of beams made from a cellular material; different degrees of variation depending on the loading conditions and lattice topology are observed and discussed.

Abstract: The metamaterial is a composite material with reasonable design. Its effective material parameters exceed the effective parameters of component materials, which shows unique properties. The concept of metamaterials has been put forward since 1960s. Nowadays, it almost involves all possible aspects of solids, from the fields of electromagnetism and optics, and mechanics and acoustics to thermology, information and other fields, and there are many research results reported, such as linear and nonlinear, reciprocal and non-reciprocal, steady and unsteady state, active and passive and so on. In this review, we start from the basics, mainly discussing the basic scope and performance characteristics of the metamaterials in optics, electromagnetism, acoustics, thermology and other emerging fields, summarizing the development process and the latest progress of theoretical design as well as experimental practices, making expectations and prospects for the future targets.

Abstract: A periodic microstructure with dielectric and metal layers is proposed to obtain a bandpass filter. The multilayer microstructure is compounded of ring cross slot and cross slot. The center frequency of the filter is 0.338THz with a 3dB bandwidth of 75.62GHz. The maximum insertion loss in the pass band reaches 0.60dB. The bandedge transitions of the rejection bands are 232dB/THz and 176dB/THz, respectively. Furthermore, the physical mechanism of near field distribution and the influence of two factors (the number of metal layer and dielectric layer) on the passband have been studied. Meanwhile, the frequency response is analyzed for different incident angles and polarizations. The frequency response characteristic is insensitive to the polarization, and a good performance for incident angle of the transmission is obtained. It can be applied to THz atmospheric communication system.

Abstract: In the rapidly growing field of additive manufacturing (AM), the focus in recent years has shifted from prototyping to manufacturing fully functional, ultralight, ultrastiff end-use parts. This research investigates the stress-strain behavior of an octahedral-and octet-truss lattice structured polyacrylate fabricated using Continuous Liquid Interface Production (CLIP) technology based on 3D printing and additive manufacturing processes. Continuous Liquid Interface Production (CLIP) is a breakthrough technology that grows parts instead of printing them layer by layer. Lattice structures such as the octahedral-and octet-truss lattice have recently attracted a lot of attention since they are often structurally more efficient than foams of a similar density made from the same material, and the ease with which these structures can now be produced using 3D printing and additive manufacturing. This research investigates the stress-strain behavior under compression of an octahedral-and octet-truss lattice structured polyacrylate fabricated using CLIP technology

Abstract: A reconfigurable THz complex medium, consisting of fundamental piezoelectric micro-devices, is introduced in this paper. By actuating the piezoelectric modules, a controllable metamaterial, presenting enhanced bandwidth tunability, is accomplished. Two diverse polarization topologies are examined, revealing the anisotropic performance of this material. The advantages of the proposed component are sufficiently clarified through several numerical data, derived by a robust finite element method (FEM).

Abstract: Finite element modeling (FEM) was used for numerical simulations of mechanical performance of aperiodic silicon-carbide scaffold manufactured by robocasting. The FEM approach enabled reliable calculation of theeffective anisotropic elastic properties of the scaffold at the macro-scale, as well as of the acoustic band structureindicating the metamaterial-like behavior of the material at the micro-scale. In addition, the micromechanics of thescaffold was discussed based on the outputs of the model: the mechanisms of the extremely soft shearing modes wereidentified and the corresponding stress concentrations arising at the contact points in the scaffold were analyzedwith respect to the possible failure modes of the robocast structure.

Abstract: In this paper, epoxy resin was used as matrix to prepare composite cryomilling at liquid nitrogen temperature in which the content of CNTs powder vary from 25 wt% to 40 wt%. The microstructure and dielectric properties of the composite were analyzed by SEM and RF impedance material analyzer. The result showed that permittivity of the composites turned negative after the CNTs reached certain content. The plasma oscillation of delocalized electrons in CNTs conductive networks causes negative permittivity phenomenon.