Now showing items 21-40 of 297

    • All-PM fiber loop mirror interferometer analysis and simultaneous measurement of temperature and mechanical vibration 

      Leandro González, Daniel Upna; López-Amo Sáinz, Manuel Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      In this work, a new all-polarization maintaining (PM) fiber loop mirror interferometer is proposed and validated as temperature and mechanical vibration sensor. The scheme employs the arms of a PM coupler as communication ...
    • 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 ...
    • Luminescence-based optical sensors fabricated by means of the layer-by-layer nano-assembly technique 

      Acha Morrás, Nerea de Upna; Elosúa Aguado, César Upna; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      Luminescence-based sensing applications range from agriculture to biology, including medicine and environmental care, which indicates the importance of this technique as a detection tool. Luminescent optical sensors are ...
    • Effects of pump pulse extinction ratio in Brillouin optical time-domain analysis sensors 

      Iribas Pardo, Haritz Upna; Mariñelarena Ollacarizqueta, Jon Upna; Feng, Cheng; Urricelqui Polvorinos, Javier Upna; Schneider, Thomas; Loayssa Lara, Alayn Upna (Optical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      We report on two previously unknown non-local effects that have been found to impair Brillouin optical time-domain analysis (BOTDA) sensors that deploy limited extinction ratio (ER) pump pulses. The first one originates ...
    • Experimental realization of an epsilon-near-zero graded-index metalens at terahertz frequencies 

      Pacheco Peña, Víctor Upna; Engheta, Nader; Kuznetsov, Sergei A.; Gentselev, Alexandr; Beruete Díaz, Miguel Upna (American Physical Society, 2017)   Artículo / Artikulua  OpenAccess
      The terahertz band has been historically hindered by the lack of efficient generators and detectors, but a series of recent breakthroughs have helped to effectively close the “terahertz gap.” A rapid development of terahertz ...
    • 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 ...
    • Annular apertures in metallic screens as extraordinary transmission and frequency selective surface structures 

      Rodríguez Ulibarri, Pablo Upna; Navarro Cía, Miguel Upna; Rodríguez Berral, Raúl; Mesa, Francisco; Medina, Francisco; Beruete Díaz, Miguel Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      A 2-D periodic array of annular apertures (or ring slots) is studied using an accurate circuit model. The model accounts for distributed and dynamic effects associated with the excitation of high-order modes operating above ...
    • Enhancement of the dynamic range in slope-assisted coherent brillouin optical time-domain analysis sensors 

      Mariñelarena Ollacarizqueta, Jon Upna; Urricelqui Polvorinos, Javier Upna; Loayssa Lara, Alayn Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      We present two techniques that provide an extension of the dynamic range of coherent Brillouin optical time-domain analysis (BOTDA) sensors for dynamic measurements. This type of BOTDA sensors rely on self-heterodyne ...
    • 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 ...
    • 3D-printed 96 GHz bull’s-eye antenna with off-axis beaming 

      Beaskoetxea Gartzia, Unai Upna; Maci, Stefano; Navarro Cía, Miguel Upna; Beruete Díaz, Miguel Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      Reducing the profile, footprint and weight of antennas embarked on aircrafts, drones or satellites has been a long pursued objective. Here we tackle this issue by developing a millimeter-wave 96 GHz elliptical Bull’s-Eye ...
    • 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. ...
    • Response of complementary split ring resonators in composite stratified substrate integrated waveguide 

      Pérez Escudero, José Manuel Upna; Jarauta Ayensa, Eduardo Upna; Falcone Lanas, Francisco Javier Upna; Beruete Díaz, Miguel Upna (American Institute of Physics, 2017)   Artículo / Artikulua  OpenAccess
      In this work, the behavior of a Complementary Split Ring Resonator (CSRR) operating within the quasi-static resonance regime and embedded in a composite stratified Substrate Integrated Waveguide (SIW) with two different ...
    • 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 ...
    • High aperture efficiency wide corrugations bull’s-eye antenna working at 60 GHz 

      Beaskoetxea Gartzia, Unai Upna; Beruete Díaz, Miguel Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      A full metallic Bull’s-Eye (BE) antenna operating at 60 GHz is numerically and experimentally analyzed. The antenna presents wide grooves, rather than narrow ones, which support higher order resonances that lead to a large ...
    • Optical fibre sensors using graphene-based materials: a review 

      Hernáez Sáenz de Zaitigui, Miguel Upna; Ruiz Zamarreño, Carlos Upna; Melendi Espina, Sonia; Bird, Liam; Mayes, Andrew; Arregui San Martín, Francisco Javier Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      Graphene and its derivatives have become the most explored materials since Novoselov and Geim (Nobel Prize winners for Physics in 2010) achieved its isolation in 2004. The exceptional properties of graphene have attracted ...
    • Recent developments in fiber optics humidity sensors 

      Ascorbe Muruzabal, Joaquín Upna; Corres Sanz, Jesús María Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      A wide range of applications such as health, human comfort, agriculture, food processing and storage, and electronic manufacturing, among others, require fast and accurate measurement of humidity. Sensors based on optical ...
    • 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 ...
    • One-way quasiplanar terahertz absorbers using nonstructured polar dielectric layers 

      Rodríguez Ulibarri, Pablo Upna; Serebryannikov, Andriy E.; Beruete Díaz, Miguel Upna (American Physical Society, 2017)   Artículo / Artikulua  OpenAccess
      A concept of quasiplanar one-way transparent terahertz absorbers made of linear isotropic materials is presented. The resulting structure consists of a homogeneous absorbing layer of polar dielectric, GaAs, a dispersion-free ...
    • Synthesis of one dimensional electromagnetic bandgap structures with fully controlled parameters 

      Arnedo Gil, Israel Upna; Chudzik, Magdalena Upna; Percaz Ciriza, Jon Mikel Upna; Arregui Padilla, Iván Upna; Teberio Berdún, Fernando Upna; Benito Pertusa, David Upna; Lopetegui Beregaña, José María Upna; Gómez Laso, Miguel Ángel Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      In this paper, we propose a novel synthesis strategy for the design of one dimensional electromagnetic bandgap (1- D-EBG) structures where all the performance parameters of these devices can fully be controlled, i.e., ...