Now showing items 360-379 of 572

    • Nanodeposition of materials with complex refractive index in long period fiber gratings 

      Del Villar, Ignacio Upna; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Achaerandio, Miguel Upna (IEEE, 2005)   Artículo / Artikulua  OpenAccess
      An overlay of higher refractive index than the cladding is deposited on a Long Period Fiber Grating (LPFG). This permits to improve in a great manner the sensitivity of the device to ambient and overlay refractive index ...
    • Nanofabrication of phase-shifted Bragg gratings on the end facet of multimode fiber towards development of optical filters and sensors 

      Gallego, E.E.; Ascorbe Muruzabal, Joaquín Upna; Del Villar, Ignacio Upna; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (Elsevier, 2018)   Artículo / Artikulua  OpenAccess
      This work describes the process of nanofabrication of phase-shifted Bragg gratings on the end facet of a multimode optical fiber with a pulsed DC sputtering system based on a single target. Several structures have been ...
    • Nanofilms on a hollow core fiber 

      Matías Maestro, Ignacio Upna; Bravo Larrea, Javier Upna; Arregui San Martín, Francisco Javier Upna; Corres Sanz, Jesús María Upna (SPIE, 2006)   Artículo / Artikulua  OpenAccess
      We experimentally study the behavior of one multimode fiber–hollow core fiber–multimode fiber structure when nanofilms are deposited on it with the aim of developing practical evanescent field-based devices, such as sensors, ...
    • Nanomaterials for functional textiles and fibers 

      Rivero Fuente, Pedro J. Upna; Urrutia Azcona, Aitor Upna; Goicoechea Fernández, Javier Upna; Arregui San Martín, Francisco Javier Upna (Springer US, 2015)   Artículo / Artikulua  OpenAccess
      Nanoparticles are very interesting because of their surface properties, different from bulk materials. Such properties make possible to endow ordinary products with new functionalities. Their relatively low cost with ...
    • Narrow-linewidth multi-wavelength random distributed feedback laser 

      Leandro González, Daniel Upna; Rota Rodrigo, Sergio Upna; Ardanaz, Diego; López-Amo Sáinz, Manuel Upna (IEEE / OSA, 2015)   Artículo / Artikulua  OpenAccess
      In this work, narrow-band emission lines are generated by means of two random distributed feedback fiber laser schemes. Spectral line-widths as narrow as 3.2 pm have been measured, which significantly improves previous ...
    • Near-field electromagnetic trapping through curl-spin forces 

      Liberal Olleta, Íñigo Upna; Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna; Ziolkowski, Richard W. (American Physical Society, 2013)   Artículo / Artikulua  OpenAccess
      Near-field electromagnetic trapping of particles is generally obtained bymeans of gradient forces. In this paper, we discuss the attractive behavior of curl-spin forces, as well as their potential for near-field ...
    • Negative refraction in a prism made of stacked subwavelength hole arrays 

      Navarro Cía, Miguel Upna; Beruete Díaz, Miguel Upna; Sorolla Ayza, Mario Upna; Campillo, Igor (Optical Society of America, 2008)   Artículo / Artikulua  OpenAccess
      Metamaterial structures are artificial materials that show unconventional electromagnetic properties such as negative refraction index, perfect lenses, and invisibility. However, losses are one of the big challenges to be ...
    • Negative refraction through an extraordinary transmission left-handed metamaterial slab 

      Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna; Sorolla Ayza, Mario Upna; Campillo, Igor (American Physical Society, 2009)   Artículo / Artikulua  OpenAccess
      In this work we present numerical and experimental results of negative refraction through a negative index metamaterial based on miniaturized extraordinary transmission stacked subwavelength hole arrays, also known as ...
    • New analytical method to design filters by combining the periodic and resonant filtering effects of EBG cells 

      Ibáñez Loinaz, Asier; Río Bocio, Carlos del Upna (IEEE, 2005)   Contribución a congreso / Biltzarrerako ekarpena  OpenAccess
      In this paper a new analytical method to design stop-band filters combining the Bragg and resonant effects is presented. A rigorous consideration of the EBG structures filtering effect at the microwave frequency range ...
    • New approach to the design of corrugated horn antennas 

      Gonzalo García, Ramón Upna; Teniente Vallinas, Jorge Upna; Río Bocio, Carlos del Upna; Sorolla Ayza, Mario Upna (1997)   Contribución a congreso / Biltzarrerako ekarpena  OpenAccess
      In this paper, we present two new corrugated horn antenna designs in circular waveguide. The first one is a converter horn antenna from monomode circular waveguide TE11 to corrugated waveguide HE11 mode in a very efficient ...
    • New developments in the THz field for imaging applications 

      Etayo Salinas, David Upna (2014)   Tesis doctoral / Doktoretza tesia  OpenAccess
      Con esta tesis se pretende avanzar en el desarrollo de la tecnología de terahercios (THz) dentro del campo de las aplicaciones de imagen. Actualmente, los THz se presentan como un rango frecuencial muy interesante para ...
    • A new muscle architecture model with non-uniform distribution of muscle fiber types 

      Navallas Irujo, Javier Upna; Malanda Trigueros, Armando Upna; Gila Useros, Luis; Rodríguez Falces, Javier Upna; Rodríguez Carreño, Ignacio Upna (World Academy of Science, Engineering and Technology, 2007)   Artículo / Artikulua  OpenAccess
      According to previous studies, some muscles present a non-homogeneous spatial distribution of its muscle fiber types and motor unit types. However, available muscle models only deal with muscles with homogeneous ...
    • New regimes to achieve enhanced transmission through subwavelength hole arrays 

      Navarro Cía, Miguel Upna; Beruete Díaz, Miguel Upna; Sorolla Ayza, Mario Upna (2011)   Contribución a congreso / Biltzarrerako ekarpena  OpenAccess
      In this communication we present millimetre- and THz-waves experimental confirmation of enhanced transmission through subwavelength hole arrays with rectangular lattice when the incident electric field is parallel to ...
    • Non-negative matrix decomposition for single-channel source separation in biomedical signal processing applications 

      Niegowski, Maciej Upna (2017)   Tesis doctoral / Doktoretza tesia  OpenAccess
      La separación de fuentes en el procesamiento de señales digitales, consiste en encontrar las mejores aproximaciones de las componentes de una mezcla de señales. Aunque en la mayoría de los casos no se dispone de antemano ...
    • Nonbianisotropic complementary split ring resonators as angular selective metasurfaces 

      Rodríguez Ulibarri, Pablo Upna; Beruete Díaz, Miguel Upna (Optical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      In this work, a metasurface with unconventional angular performance and composed by a nonbianisotropic complementary split ring resonator (NB-CSRR) is analyzed numerically and experimentally. A numerical study comparing ...
    • Nonlinear dynamics of vertical-cavity surface-emitting lasers 

      Panajotov, Krassimir; Sciamanna, Marc; Gatare, Ignace; Arizaleta Arteaga, Mikel Upna; Thienpont, Hugo (Hindawi / Wiley, 2011)   Artículo / Artikulua  OpenAccess
      Nonlinear dynamics of Vertical-Cavity Surface-Emitting Lasers (VCSELs) induced by optical injection, optical feedback, current modulation and mutual coupling is reviewed. Due to the surface emission and cylindrical symmetry ...
    • A novel design method for phase-locked loops of any order and type 

      Carlosena García, Alfonso Upna; Mànuel Lázaro, Antonio (IEEE, 2006)   Contribución a congreso / Biltzarrerako ekarpena  OpenAccess
      In this paper a novel approach to the design of PLLs is presented, which can be used regardless of their Order and Type. The method stems from the fact that high-frequency poles in the loop filter determine filtering ...
    • Novel highly sensitive protein sensors based on tapered optical fibres modified with Au-based nanocoatings 

      Urrutia Azcona, Aitor Upna; Bojan, Kartheka; Marques, Leonel; Mullaney, Kevin; Goicoechea Fernández, Javier Upna; James, Stephen; Clark, Matt; Tatam, Ralph; Korposh, Sergiy (Hindawi Publishing Corporation, 2016)   Artículo / Artikulua  OpenAccess
      Novel protein sensors based on tapered optical fibres modified with Au coatings deposited using two different procedures are proposed. Au-based coatings are deposited onto a nonadiabatic tapered optical fibre using (i) a ...
    • A novel PLL architecture 

      Osa, Juan I.; Carlosena García, Alfonso Upna; López Martín, Antonio Upna (2000)   Contribución a congreso / Biltzarrerako ekarpena  OpenAccess
      A novel phase-locked loop scheme is proposed in this paper, whose main distinguishing features are infinite hold-in range, pull-out range fractionally constant and also a ripple fractionally constant. To this end, it ...
    • Novel sensor design using photonic crystal fibres for monitoring the onset of corrosion in reinforced concrete structures 

      McCague, Colum; Fabian, Matthias; Karimi, Mohammad; Bravo Acha, Mikel Upna; Jaroszewicz, Leszek R. (IEEE, 2014)   Artículo / Artikulua  OpenAccess
      In this paper, a novel sensing technique has been designed and investigated for the direct, in situ detection of steel corrosion distributed in reinforced concrete structures. At present, structural health monitoring in ...