A Novel Approach for Designing Omnidirectional Slotted-Waveguide Antenna Array

This paper presents a novel design of a high-gain omnidirectional slotted-waveguide antenna array for 5G mm-wave applications. The structure is based on a circular waveguide filled with teflon for manipulating its dimension. It provides 12,1 dBi gain and omnidirectional coverage in the azimuth plane with only 1.3 dB deviation, which is ensured by making use of a twisting technique for proper placing the slots into the waveguide walls. A bandwidth of 1.61 GHz centered at 26.2 GHz has been numerically demonstrated

Applicability of low macrobending loss hollow-core PCF to FTTH applications

Fiber-To-The-Home (FTTH) technology has been significantly implemented in access networks, providing very high data rates transmission and a variety of digital content to subscribers. It involves an optical cable link being installed between the building entry point and each subscriber with the Multiple Dwelling Units (MDUs), i.e. flats and apartments. In other words, optical cable has to lie fairly straight to carry a strong signal, since typically is necessary to bend, twist and turn the lines in and out of tight corners without degrading the link connection. In this paper we propose the use of Hollow-Core Photonic Crystal Fiber (HC-PCF) for FTTH applications. It is presented an experimental analysis of the macrobending effects in a HC-PCF based on a comparison with traditional fibers and by following the ITU-T G.657B standard recommendations. We observe this fiber, with only 6.5 µm core, is bending loss insensitive, even at extremely small bending radius of 2 mm, in which it presents a loss of only 0.58 dB.251258Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Experimental characterization of a catalytically active flagellin variant in Clostridium haemolyticum

The bacterial flagellum is made up of approximately 20,000 subunits of the monomeric protein, flagellin, and plays a role in cell motility and pathogenesis. The extreme sequence diversity within the hypervariable region of flagellin genes observed across phyla suggests hidden functional diversity. This thesis outlines the discovery of the first family of flagellin variants with proteolytic activity. A multi-faceted approach revealed a conserved HExxH motif within the hypervariable region (HVR) of these flagellin variants. The motif is characteristic of the Gluzincin family of thermolysin-like peptidases and was found to be conserved in 74 bacterial species spanning over 32 genera. Experimental validation began with the recombinant expression and purification of the HVR of the flagellin FliA(H) from the species Clostridium haemolyticum, an animal pathogen. An approach using mass spectrometry and proteomics revealed that the substrate specificity of this flagellin protease is similar to that of zinc-dependant matrix metallopeptidases (MMPs). Furthermore, peptide sequencing of harvested C.haemolyticum flagellar filaments revealed that the proteolytic flagellin was the second most dominant flagellin component and was also shown to have MMP-like protease activity. Considering the expanded functional repertoire of this organelle in the recent years, this flagellin-associated protease may play a role in chemotaxis, biofilm formation, adhesion and pathogenesis

Recent Progress And Novel Applications Of Photonic Crystal Fibers

Photonic crystal fibers present a wavelength-scale periodic microstructure running along their length. Their core and two-dimensional photonic crystal might be based on varied geometries and materials, enabling light guidance due to different propagation mechanisms in an extremely large wavelength range, extending to the terahertz regions. As a result, these fibers have revolutionized the optical fiber technology by means of creating new degrees of freedom in the fiber design, fabrication and applicability. This report aims to provide a detailed statement on the recent progress and novel potential applications of photonic crystal fibers. © 2010 IOP Publishing Ltd.732Russell, P.S.J., A neat idea (2001) IEE Rev., 47, pp. 19-23Russell, P.S.J., Photonic crystal fibers (2003) Science, 299, pp. 358-362Knight, J., Birks, T., Russell, P.S.J., Atkin, D., All-silica single-mode fiber with photonic crystal cladding (1996) Opt. 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A low-profile and ultra-wideband printed antenna with a 176% bandwidth

Abstract This work reports the development of a simple, low-profile and ultra-wideband printed antenna. The proposed antenna is based on a truncated ground plane and an impedance matching structure formed by a round junction and two chamfers; these modifications significantly increase the antenna frequency bandwidth compared to conventional microstrip antennas and ultra-wideband printed monopoles published in literature. An antenna prototype was fabricated using an Arlon DiClad 880 substrate with an electrical permittivity of 2.2. A bandwidth of 176% was attained at a central frequency of 14.9 GHz (ranging from 1.79 to 28.02 GHz). Numerical simulations and experimental results of the antenna's radiation pattern are also reported and exhibit good agreement. To the best of our knowledge, this is the widest bandwidth from a printed antenna that has been published in the literature

Material Characterization and Propagation Analysis of mm-Waves Indoor Networks

Abstract This paper reports detailed propagation analyses of mm-wave indoor networks based numerical simulations of the wireless coverage and measurements of the propagation coefficient at 28 and 38 GHz. Additionally, material characterization of typical buildings materials used in constructions are presented, including: common brick (with and without electrical installations); plaster walls; glazing, Eucatex panels; wooden doors. The computational simulations have been performed using Altair WinProp™ software in order to predict path loss in LOS (Line-of-Sight) and NLOS (Non-Line-of-Sight) environments. The obtained results contributes to the planning of the fifth Generation of mobile communications networks (5G), operating in mm-waves

Birefringence Properties Of Hybrid Photonic Crystal Fibers

We present a fabrication and an experimental investigation of the birefringent properties of a Highly Birefrigent Hybrid Photonic Crystal Fiber. Polarization dependent loss as high as 21 dB is experimentally obtained on the photonic bandgap edges. ©2009IEEE.804805Knight, J.C., Photonic Crystal Fibres (2003) Nature, 424, pp. 847-851. , AugustArismar Cerqueira Jr., S., Luan, F., Cordeiro, C.M.B., George, A.K., Knight, J.C., Hybrid photonic crystal fiber (2006) Optics Express, 14, pp. 926-931Arismar Cerqueira Jr., S., Cordeiro, C.M.B., Biancalana, F., Roberts, P.J., Hernandez-Figueroa, H.E., Brito Cruz, C.H., Hybrid photonic crystal fiber,Nonlinear interaction between two different photonic bandgaps of a Hybrid Photonic Crystal Fiber (2008) Optics Letters, 33. , SeptemberSchreiber, T., Stress-induced single-polarization single-transverse mode photonic crystal fiber with low nonlinearity (2005) Optics Express, 13, pp. 7621-763