Now showing items 63-76 of 76

    • Sensitivity enhancement in low cutoff wavelength long-period fiber gratings by cladding diameter reduction 

      Del Villar, Ignacio Upna; Partridge, Matthew; Rodríguez, Wenceslao; Fuentes, Omar; Socorro Leránoz, Abián Bentor Upna; Díaz Lucas, Silvia Upna; Corres Sanz, Jesús María Upna; James, Stephen; Tatam, Ralph (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      The diameter of long-period fiber gratings (LPFGs) fabricated in optical fibers with a low cutoff wavelength was be reduced by hydrofluoric acid etching, enhancing the sensitivity to refractive index by more than a factor ...
    • Sensitivity optimization with cladding-etched long period fiber gratings at the dispersion turning point 

      Del Villar, Ignacio Upna; Cruz, José Luis; Socorro Leránoz, Abián Bentor Upna; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (Optical Society of America, 2016)   Artículo / Artikulua  OpenAccess
      This work presents a refractive index sensor based on a long period fiber grating (LPFG) made in a reduced cladding fiber whose low order cladding modes have the turning point at large wavelengths. The combination of ...
    • A simplified design inline microstrip-to-waveguide transition 

      Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna; Pérez Escudero, José Manuel Upna; Torres García, Alicia E. Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      A simplified design of an inline transition between microstrip and rectangular waveguide is presented in this paper. The transition makes use of a dielectric filled rectangular waveguide (DFRW) as an intermediate step, ...
    • Spatial characterization of radio propagation channel in urban vehicle-to-infrastructure environments to support WSNs deployment 

      Granda, Fausto; Azpilicueta Fernández de las Heras, Leyre Upna; Vargas Rosales, César; López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      Vehicular ad hoc Networks (VANETs) enable vehicles to communicate with each other as well as with roadside units (RSUs). Although there is a significant research effort in radio channel modeling focused on vehicle-to-vehicle ...
    • Steering surface plasmons with a graded index dielectric medium 

      Beruete Díaz, Miguel Upna; Pacheco-Peña, Víctor Upna (IOP Publishing, 2018)   Artículo / Artikulua
      The arbitrary control of surface plasmon (SP) propagation has become an intense research topic for several decades. This is due to the fact that they can be used in a variety of fields such as optical trapping, nanoantennas ...
    • Study of optical fiber sensors for cryogenic temperature measurements 

      Miguel Soto, Verónica de; Leandro González, Daniel Upna; López Aldaba, Aitor Upna; Beato López, Juan Jesús; Pérez de Landazábal Berganzo, José Ignacio; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      In this work, the performance of five different fiber optic sensors at cryogenic temperatures has been analyzed. A photonic crystal fiber Fabry-Pérot interferometer, two Sagnac interferometers, a commercial fiber Bragg ...
    • Super-oscillatory metalens at terahertz for enhanced focusing with reduced side lobes 

      Legaria Lerga, Santiago; Pacheco-Peña, Víctor Upna; Beruete Díaz, Miguel Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      In this paper, we design and numerically demonstrate an ultra-thin super-oscillatory metalens with a resolution below the diffraction limit. The zones of the lens are implemented using metasurface concepts with hexagonal ...
    • TBDClust: time-based density clustering to enable free browsing of sites in pay-per-use mobile Internet providers 

      Torres, Luis Miguel; Magaña Lizarrondo, Eduardo Upna; Morató Osés, Daniel Upna; García-Jiménez, Santiago Upna; Izal Azcárate, Mikel Upna (Elsevier, 2017)   Artículo / Artikulua  OpenAccess
      The World Wide Web has evolved rapidly, incorporating new content types and becoming more dynamic. The contents from a website can be distributed between several servers, and as a consequence, web traffic has become ...
    • Technical and environmental characterization of hydraulic and alkaline binders 

      Espuelas Zuazu, Sandra; Echeverría, Angel María; Marcelino Sádaba, Sara; Prieto Cobo, Eduardo; Seco Meneses, Andrés (Elsevier, 2018)   Artículo / Artikulua
      Portland cement is a widely used binder in construction and building applications because of its good properties. Despite its convenience as construction material, the social demands and policies trends are requesting a ...
    • Temperature sensor using a multiwavelength erbium-doped fiber ring laser 

      Díaz Lucas, Silvia Upna; San Fabián García, Noé; Socorro Leránoz, Abián Bentor Upna; Matías Maestro, Ignacio Upna (Hindawi, 2017)   Artículo / Artikulua  OpenAccess
      A novel temperature sensor is presented based on a multiwavelength erbium-doped fiber ring laser.The laser is comprised of fiber Bragg grating reflectors as the oscillation wavelength selecting filters.The performance of ...
    • THz sensing with anomalous extraordinary optical transmission hole arrays 

      Jáuregui López, Irati; Rodríguez Ulibarri, Pablo Upna; Kuznetsov, Sergei A.; Nikolaev, Nazar A.; Beruete Díaz, Miguel Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      Subwavelength hole array (HA) metasurfaces support the so-called extraordinary optical transmission (EOT) resonance that has already been exploited for sensing. In this work, we demonstrate the superior performance of a ...
    • Tunable deflection and asymmetric transmission of THz waves using a thin slab of graphene-dielectric metamaterial, with and without ENZ components 

      Serebryannikov, Andriy E.; Hajian, Hodjat; Beruete Díaz, Miguel Upna; Ozbay, Ekmel; Vandenbosch, Guy A. E. (Optical Society of America, 2018)   Artículo / Artikulua  OpenAccess
      Tunable deflection of obliquely incident, linearly polarized terahertz waves is theoretically studied in a wide frequency range around 20 THz, by combining a thin slab of graphene-dielectric metamaterial (with ten layers ...
    • Unbalanced interval-valued OWA operators 

      Miguel Turullols, Laura de Upna; Bustince Sola, Humberto Upna; Barrenechea Tartas, Edurne Upna; Pagola Barrio, Miguel Upna; Fernández Fernández, Francisco Javier Upna (Springer Berlin Heidelberg, 2016)   Artículo / Artikulua  OpenAccess
      In this work, we introduce a new class of functions defned on the interval-valued setting. These functions extend classical OWA operators but allow for diferent weighting vectors to handle the lower bounds and the ...
    • Wideband backscattering reduction at terahertz using compound reflection grating 

      Orazbayev, Bakhtiyar Upna; Rodríguez Ulibarri, Pablo Upna; Beruete Díaz, Miguel Upna (Optical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      Backscattering reduction is usually achieved by using either absorbers or diffractions gratings at the expense of a narrow bandwidth. In this paper, we propose a different strategy based on a metallic compound reflection ...