Now showing items 75-94 of 99

    • 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, ...
    • Simultaneous strain and temperature multipoint sensor based on microstructured optical fiber 

      López Aldaba, Aitor Upna; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      In this paper, a new sensor system for simultaneous and independent multipoint strain and temperature measurements is presented. The interrogation of the sensing heads has been carried out by monitoring their FFT phase ...
    • Smart cities, IoT y salud: retos de Internet of medical things (IoMT) 

      Trigo Vilaseca, Jesús Daniel; Serrano Arriezu, Luis Javier Upna; Astrain Escola, José Javier Upna; Falcone Lanas, Francisco Javier Upna (Sociedad Española de Informática de la Salud, 2018)   Artículo / Artikulua  OpenAccess
      La innovación tecnológica aplicada al ámbito de la salud está permitiendo el rápido desarrollo de la internet de los dispositivos médicos, o en su versión inglesa más aceptada internet of medical things (iomt). En este ...
    • SnO2-MOF-Fabry-Perot optical sensor for relative humidity measurements 

      López Aldaba, Aitor Upna; López Torres, Diego Upna; Elosúa Aguado, César Upna; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; Arregui San Martín, Francisco Javier Upna; López-Amo Sáinz, Manuel Upna (Elsevier, 2018)   Artículo / Artikulua
      In this paper, a new optical fiber sensor for relative humidity measurements is presented and characterized. The sensor is based on a SnO2 sputtering deposition on a microstructured optical fiber (MOF) low-finesse Fabry-Pérot ...
    • 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  OpenAccess
      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 ...
    • Strong angular dependence of resonant states in 2D dielectric cylinder rings 

      Andueza Unanua, Ángel María; Pérez Conde, Jesús Upna; Sevilla Moróder, Joaquín Upna (AIP Publishing, 2018)   Artículo / Artikulua
      We investigate collective resonators made of dielectric cylinders assembled as two-dimensional regular octagons and decagons. These structures exhibit collective resonance states that change their intensity with the incident ...
    • 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 class AB RFC OTA using non-linear current mirrors 

      Garde Luque, María Pilar; López Martín, Antonio Upna; Carvajal, Ramón G.; Galan, J.A.; Ramírez-Angulo, Jaime (Institution of Engineering and Technology, 2018)   Artículo / Artikulua  OpenAccess
      An alternative approach to the design of super class AB recycling folded cascode operational transconductance amplifiers is proposed. Instead of using local common-mode feedback for boosting dynamic currents, simple current ...
    • Super class AB RFC OTA with adaptive local common-mode feedback 

      Garde Luque, María Pilar; López Martín, Antonio Upna; Carvajal, Ramón G.; Ramírez-Angulo, J. (Institution of Engineering and Technology, 2018)   Artículo / Artikulua  OpenAccess
      A super class AB recycling folded cascode operational transconductance amplifier is presented. It employs local common-mode feedback using two matched tuneable active resistors, allowing to adapt the amplifier to different ...
    • 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 ...
    • Supercapacitors: electrical characteristics, modelling, applications and future trends 

      Berrueta Irigoyen, Alberto; Ursúa Rubio, Alfredo Upna; San Martín Biurrun, Idoia Upna; Eftekhari, Ali; Sanchís Gúrpide, Pablo Upna (IEEE, 2019)   Artículo / Artikulua  OpenAccess
      Energy storage systems are playing an increasingly important role in a variety of applications, such as electric vehicles or grid-connected systems. In this context, supercapacitors (SCs) are gaining ground due to their ...
    • 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 ...
    • Tunable SESAM-based mode-locked soliton fiber laser in linear cavity by axial-strain applied to a FBG 

      Aporta, I.; Leandro González, Daniel Upna; Quintela, M. A.; Pérez Herrera, Rosa Ana Upna; López-Amo Sáinz, Manuel Upna; López Higuera, José Miguel (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      A self-started stable tunable mode-locked (ML) soliton fiber laser in a linear cavity structure composed by commercial passive elements is presented in this paper. It is based on the combination of an Erbium doped fiber ...