Design and Characterization of a Compact Single Layer Modified S-Shaped Tag Antenna for UHF-RFID Applications

In this paper, we report the design of a new compact single layer modified S-shaped tag antenna for UHF-RFID applications. To achieve a compact size of 51×34 mm2 for this tag antenna, the technique of using S shaped strip is applied, and by further adding a pair of equilateral triangular stubs into this structure, good impedance matching can be obtained at 915 MHz, which is the center frequency of the North-American UHF-RFID band (902 to 928 MHz). Besides exhibiting acceptable 5m read range in free space at 915 MHz, the proposed design shows a read range of about 4.5 when mounted on a metallic object (200 ×30 cm2) separated by spacer foam of thickness 1 cm. Furthermore, the proposed design shows a reasonable read ranges when it is mounted on different dielectrics with low permittivity. The proposed design has a simple configuration, low cost, acceptable read range, and can work on various background materials. &nbsp

Extraordinary THz Transmission with a Small Beam Spot:the Leaky Wave Mechanism

The discovery of extraordinary optical transmission (EOT) through patterned metallic foils in the late 1990s was decisive for the development of plasmonics and cleared the path to employ small apertures for a variety of interesting applications all along the electromagnetic spectrum. However, a typical drawback often found in practical EOT structures is the large size needed to obtain high transmittance peaks. Consequently, practical EOT arrays are usually illuminated using an expanded (mimicking a plane wave) beam. Here, it is shown with numerical and experimental results in the THz range that high transmittance peaks can be obtained even with a reduced illumination spot exciting a small number of holes, provided that the structure has a sufficient number of lateral holes out of the illumination spot. These results shed more light on the prominent role of leaky waves in the underlying physics of EOT and have a direct impact on potential applications

Terahertz metamaterials on flexible polypropylene substrate

The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-014-9724-1In this work, we present a metamaterial working at terahertz frequencies made over a flexible polypropylene sub-strate. The experimental measurements, in accordance with the numerical calculations, show the metamaterial reliance on the impinging electric field polarization. The structure s symmetry yields purely electrical resonant responses eliminating bianisotropy effects. The widely used bendable polypropylene polymer may promote the insertion of metamaterial-based structures with special electromagnetic response in a number of objects of our daily lives such as textiles, automotive components, and sensingThis work was supported by the Spanish MICINN under contracts CONSOLIDER EMET CSD2008-00066 and TEC2011-28664-C02-02 and by the Universitat Politecnica de Valencia under the program INNOVA 2011.Ortuño Molinero, R.; García Meca, C.; Martínez Abietar, AJ. (2014). Terahertz metamaterials on flexible polypropylene substrate. Plasmonics. 9(5):1143-1147. https://doi.org/10.1007/s11468-014-9724-1S1143114795Smith DR, Padilla WJ, Vier DC, Nemat-Nasser SC, Schultz S (2000) Composite medium with simultaneously negative permeability and permittivity. Phys Rev Lett 84:4184–4187Pendry JB (2000) Negative refraction makes a perfect lens. Phys Rev Lett 85:3966–3969Zhang X, Liu Z (2008) Superlenses to overcome the diffraction limit. Nat Mater 7:435–441Pendry JB, Schurig D, Smith DR (2006) Controlling electromagnetic fields. Science 312:1780–1782Schurig D, Mock JJ, Justice BJ, Cummer SA, Pendry JB, Starr AF, Smith DR (2006) Metamaterial electromagnetic cloak at microwave frequencies. Science 314:977–980Rodríguez-Cantó PJ, Martínez-Marco M, Rodríguez-Fortuño FJ, Tomás-Navarro B, Ortuño R, Peransí-Llopis S, Martínez A (2011) Demonstration of near infrared gas sensing using gold nanodisks on functionalized silicon. 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A dual band compact antenna with SSR for wireless communication systems

International audienc

A new modified S-shaped compact antenna for RFID-UHF tag applications

International audienc

Mutual coupling Reduction in antenna arrays using Metasurface

In this paper, a meta-surface is developed as an effective solution for reducing mutual coupling between two adjacent antennas. The meta-surface comprises an array of omega shape resonators placed above two closely antennas. The simulated results show a 24 dB reduction in coupling when placing meta-surface over two adjacent antennas separated by a spacing of 1/5 wavelength at frequency of 2.85 GHz. Furthermore, the gain of antenna arrays with the meta-surface is also improved by 3dB

Planar holographic metasurfaces for terahertz focusing.

Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (also called metamirrors) designed for focusing terahertz radiation into a single spot and four spaced spots are proposed and experimentally investigated at the frequency of 0.35 THz. Each metasurface is designed using a computer-generated spatial distribution of the reflection phase. The phase variation within 360 deg is achieved via a topological morphing of the metasurface pattern from metallic patches to U-shaped and split-ring resonator elements, whose spectral response is derived from full-wave electromagnetic simulations. The proposed approach demonstrates a high-performance solution for creating low-cost and lightweight beam-shaping and beam-focusing devices for the terahertz band.This work was supported by the Ministry of Education and Science of the Russian Federation under the State Assignment Contract #3002 (implementation of the Gerchberg-Saxton iterative algorithm and experimental testing), the Russian Science Foundation under the Project 14-12-01037 (full-wave electromagnetic simulations), and the Spanish Government under contracts Consolider “Engineering Metamaterials” CSD2008-00066, and TEC2011-28664-C01. M. Beruete acknowledges funding by the Spanish Government under the research contract program Ramón y Cajal RYC-2011-08221. M. N.-C. was supported by Imperial College London through a Junior Research Fellowship

Wide Angle, Polarization Independent Metamaterial Absorber Unit-Cell for RCS Reduction and Energy Harvesting Applications

International audienceIn this paper, a new design of Metamaterial Absorber unit-cell is presented with a high absorption coefficient of 99.78% at 10 GHz. The numerical results show that the proposed unit-cell has constant performances regardless the polarization state of the incoming waves, a wide angle of absorption up to 70 • for TE polarized waves, and 80 • for TM, RHCP, LHCP polarized waves is achieved. Analytical circuit model has been developed to describe the matching process between the unit-cell and free space impedances. The monostatic RCS capability of 12 × 12 metasurface array has been proved numerically by full wave simulation showing more than 10 dB RCS reduction at normal and oblique incidences. Finally a metasurface array was fabricated and tested experimentally, the simulated and measured results are in good agreement in terms of absorption rate and bandwidth, expect a frequency shift in terms of resonance frequency