• Optimized strain long-period fiber grating (LPFG) sensors operating at the dispersion turning point 

      Del Villar, Ignacio Upna; Fuentes, Omar; Chiavaioli, Francesco; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      Two phenomena for enhancing the sensitivity of longperiod fiber gratings are combined toward an increase of the sensitivity to strain of this type of devices: the dispersion turning point (DTP) and the cladding diameter ...
    • 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
      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 ...
    • Ku band low profile asymmetric Bull’s-Eye antenna with reduced side lobes and monopole feeding 

      Beaskoetxea Gartzia, Unai Upna; Torres García, Alicia E. Upna; Beruete Díaz, Miguel Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      In this paper, a linearly polarized low profile and asymmetric Bull’s-Eye leaky wave antenna fed by a monopole operating at 13 GHz is presented. Broadside radiation from the monopole is achieved by surrounding it with an ...
    • Extraordinary THz transmission with a small beam spot: the leaky wave mechanism 

      Navarro Cía, Miguel Upna; Pacheco Peña, Víctor Upna; Kuznetsov, Sergei A.; Beruete Díaz, Miguel Upna (Wiley, 2018)   Artículo / Artikulua
      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 ...
    • Application of two different methods for extending lattice-valued restricted equivalence functions used for constructing similarity measures on L-fuzzy sets 

      Palmeira, Eduardo S.; Bedregal, Benjamin; Bustince Sola, Humberto Upna; Paternain Dallo, Daniel Upna; Miguel Turullols, Laura de Upna (Elsevier, 2018)   Artículo / Artikulua
      Based on previous investigations, we have proposed two different methods to extend lattice-valued fuzzy connectives (t-norms, t-conorms, negations and implications) and other related operators, considering a generalized ...
    • Multivalued contexts associated with criteria 

      Alcalde, Cristina; Burusco Juandeaburre, Ana (Taylor & Francis, 2018)   Artículo / Artikulua
      We are interested in the study of L-fuzzy contexts taking into account different criteria. These contexts arise when we want to analyze the relationship between objects and attributes from different points of view. ...
    • Metasurface-based ultrathin carpet cloaks for millimeter waves 

      Orazbayev, Bakhtiyar Upna; Mohammadi Estakhri, Nasim; Alù, Andrea; Beruete Díaz, Miguel Upna (2017)   Artículo / Artikulua  OpenAccess
      A metasurface carpet cloak for millimetre-wave range with polarization independent performance is experimentally demonstrated. It is shown that the cloak is able to mimic the ground plane by fully restoring the amplitude ...
    • Binary relations coming from solutions of functional equations: orderings and fuzzy subsets 

      Campión Arrastia, María Jesús Upna; Miguel Turullols, Laura de Upna; García Catalán, Olga Raquel Upna; Induráin Eraso, Esteban Upna; Abrísqueta Usaola, Francisco Javier Upna (World Scientific Publishing Company, 2017)   Artículo / Artikulua
      We analyze the main properties of binary relations, defined o n a nonempty set, that arise in a natural way when dealing with real-valued functions that satisfy certain classical functional equations on two variables. We ...
    • Is there a frontier in sensitivity with lossy mode resonance (LMR) based refractometers? 

      Ozcariz Celaya, Aritz Upna; Ruiz Zamarreño, Carlos Upna; Zubiate Orzanco, Pablo Upna; Arregui San Martín, Francisco Javier Upna (Nature Publishing Group, 2017)   Artículo / Artikulua  OpenAccess
      A tin dioxide thin layer has been studied in order to improve the sensitivity of lossy mode resonances (LMR) based sensors. The effects of the thin film thickness and the polarization of light in a SnO2 coated D-shaped ...
    • Optimization in nanocoated D-shaped optical fiber sensors 

      Del Villar, Ignacio Upna; Zubiate, Pablo; Ruiz Zamarreño, Carlos Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (Optical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      Nanocoated D-shaped optical fibers have been proven as effective sensors. Here, we show that the full width at half minimum (FWHM) of lossy mode resonance can be reduced by optimizing the nanocoating width, thickness and ...
    • Increasing the sensitivity of an optic level sensor with a wavelength and phase sensitive single-mode multimode single-mode (SMS) fiber structure 

      Fuentes, Omar; Del Villar, Ignacio Upna; Vento, José R.; Socorro Leránoz, Abián Bentor Upna; Gallego, E.E.; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      The sensitivity of a liquid level sensor based on a single-mode-multimode-single-mode fiber structure has been increased by hydrofluoric acid etching. The etching process was analyzed and monitored both theoretical and ...
    • 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 ...
    • Challenges in wireless system integration as enablers for indoor context aware environments 

      López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      The advent of fully interactive environments within Smart Cities and Smart Regions requires the use of multiple wireless systems. In the case of user-device interaction, which finds multiple applications such as Ambient ...
    • Humidity sensor based on Bragg gratings developed on the end facet of an optical fiber by sputtering of one single material 

      Ascorbe Muruzabal, Joaquín Upna; Corres Sanz, Jesús María Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      The refractive index of sputtered indium oxide nanocoatings has been altered just by changing the sputtering parameters, such as pressure. These induced changes have been exploited for the generation of a grating on the ...
    • Non-local effects in Brillouin optical time-domain analysis sensors 

      Iribas Pardo, Haritz Upna; Urricelqui Polvorinos, Javier Upna; Mompó Roselló, Juan José Upna; Mariñelarena Ollacarizqueta, Jon Upna; Loayssa Lara, Alayn Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      Brillouin optical time-domain analysis (BOTDA) sensors have great potential to provide distributed measurements of temperature and strain over large structures with high spatial resolution and measurement precision. However, ...
    • An analysis matrix for the assessment of smart city technologies: main results of its application 

      Branchi, Pablo Emilio; Fernández Valdivielso, Carlos Upna; Matías Maestro, Ignacio Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      The paper presents the main results of a previously developed methodology to better evaluate new technologies in Smart Cities, using a tool to evaluate different systems and technologies regarding their usefulness, considering ...
    • 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 ...
    • Cyclic coding for Brillouin optical time-domain analyzers using probe dithering 

      Iribas Pardo, Haritz Upna; Loayssa Lara, Alayn Upna; Sauser, Florian; Llera, Miguel; Le Floch, Sébastien (Optical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      We study the performance limits of mono-color cyclic coding applied to Brillouin optical time-domain analysis (BOTDA) sensors that use probe wave dithering. BOTDA analyzers with dithering of the probe use a dual-probe-sideband ...
    • Mid-infrared spectroscopy (MIR) for simultaneous determination of fat and protein content in meat of several animal species 

      Lozano Saiz, María; Rodríguez Ulibarri, Pablo Upna; Echeverría Morrás, Jesús Upna; Beruete Díaz, Miguel Upna; Sorolla Ayza, Mario Upna; Beriain Apesteguía, María José Upna (Springer, 2017)   Artículo / Artikulua
      The aim of this research was to study the application of MIR spectroscopy as an alternative to conventional methods to determine fat and protein content. Samples of the main species used to produce meat products were ...
    • Characterization of microring filters for differential group delay applications 

      Doménech, D.; Chamorro Posada, P.; Fraile Pelaez, F.J.; Erro Betrán, María José Upna; Tainta Ausejo, Santiago Upna; Muriel, M.A.; Baños, R.; Bolten, J.; Kleinjans, H. (IEEEOptical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      The longitudinal offset technique permits to improve the accuracy of the coupling coefficients of integrated directional couplers and provides designs that can be easily implemented with current fabrication tolerances. ...