Now showing items 199-218 of 297

    • Overcoming non-local effects and Brillouin threshold limitations in Brillouin optical time domain sensors 

      Ruiz Lombera, Rubén; Urricelqui Polvorinos, Javier Upna; Sagüés García, Mikel Upna; Mirapeix, Jesús; López Higuera, José Miguel; Loayssa Lara, Alayn Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      We demonstrate, for the first time to our knowledge, a Brillouin optical time domain analysis (BOTDA) sensor that is able to operate with a probe power larger than the Brillouin threshold of the deployed sensing fiber ...
    • Parameter-independent control for battery chargers based on virtual impedance emulation 

      Urtasun Erburu, Andoni Upna; Berrueta Irigoyen, Alberto; Sanchis Gúrpide, Pablo Upna; Marroyo Palomo, Luis Upna (IEEE, 2018)   Artículo / Artikulua
      An effective battery voltage regulation is fundamental to extend battery lifetime and to avoid overvoltage. However, the design of this regulation is complicated due to the wide battery impedance range, which, when dealing ...
    • Passive microwave component design using inverse scattering: theory and applications 

      Arnedo Gil, Israel Upna; Arregui Padilla, Iván Upna; Chudzik, Magdalena Upna; Teberio Berdún, Fernando Upna; Lujambio Genua, Aintzane Upna; Benito Pertusa, David Upna; Lopetegui Beregaña, José María Upna; Gómez Laso, Miguel Ángel Upna (Hindawi, 2013)   Artículo / Artikulua  OpenAccess
      We briefly review different synthesis techniques for the design of passive microwave components with arbitrary frequency response, developed by our group during the last decade. We provide the theoretical foundations based ...
    • Performance analysis of IEEE 802.15.4 compliant wireless devices for heterogeneous indoor home automation environments 

      Nazábal Urriza, Juan Antonio Upna; López Iturri, Peio Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Falcone Lanas, Francisco Javier Upna; Fernández Valdivielso, Carlos Upna (Hindawi, 2012)   Artículo / Artikulua  OpenAccess
      The influence of topology as well as morphology of complex indoor scenarios in the deployment of wireless sensor networks and wireless systems applied to home and building automation systems is analyzed. The existence of ...
    • Performance analysis of ZigBee wireless networks for AAL through hybrid ray launching and collaborative filtering 

      López Iturri, Peio Upna; Casino, Fran; Aguirre Gallego, Erik Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Falcone Lanas, Francisco Javier Upna; Solanas, Agusti (Hindawi, 2016)   Artículo / Artikulua  OpenAccess
      This paper presents a novel hybrid simulation method based on the combination of an in-house developed 3D ray launching algorithm and a collaborative filtering (CF) technique, which will be used to analyze the performance ...
    • Phase reversal technique applied to fishnet metalenses 

      Pacheco-Peña, Víctor Upna; Minin, Igor V.; Minin, Oleg V.; Beruete Díaz, Miguel Upna (Hindawi, 2018)   Artículo / Artikulua  OpenAccess
      In this work, the fishnet metamaterial is applied to several converging metalenses by combining the zoning, reference phase, and phase reversal techniques. First, the zoning and reference phase techniques are implemented ...
    • Phasorial differential pulse-width pair technique for long-range Brillouin optical time-domain analysis sensors 

      Urricelqui Polvorinos, Javier Upna; Sagüés García, Mikel Upna; Loayssa Lara, Alayn Upna (Optical Society of America, 2014)   Artículo / Artikulua  OpenAccess
      We introduce a novel phasorial differential pulse width pair (PDPP) method for Brillouin optical time domain analysis (BOTDA) sensors that combines spatial resolution enhancement with increased tolerance to non local ...
    • Photonic crystal fiber temperature sensor based on quantum dot nanocoatings 

      Larrión Zabaleta, Beatriz; Hernáez Sáenz de Zaitigui, Miguel Upna; Arregui San Martín, Francisco Javier Upna; Goicoechea Fernández, Javier Upna; Bravo Larrea, Javier Upna; Matías Maestro, Ignacio Upna (Hindawi / Wiley, 2009)   Artículo / Artikulua  OpenAccess
      Quantum dot nanocoatings have been deposited by means of the Layer-by-Layer technique on the inner holes of Photonic Crystal Fibers (PCFs) for the fabrication of temperature sensors. The optical properties of these sensors ...
    • Photonic crystal fibers for sensing applications 

      Rodrigues Pinto, Ana Margarida Upna; López-Amo Sáinz, Manuel Upna (Hindawi Publishing Corporation, 2012)   Artículo / Artikulua  OpenAccess
      Photonic crystal fibers are a kind of fiber optics that present a diversity of new and improved features beyond what conventional optical fibers can offer. Due to their unique geometric structure, photonic crystal fibers present ...
    • Planar holographic metasurfaces for terahertz focusing 

      Kuznetsov, Sergei A.; Astafev, Mikhail A.; Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna (Springer Nature, 2015)   Artículo / Artikulua  OpenAccess
      Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can ...
    • Planar magnetoinductive wave transducers: theory and applications 

      Freire, M. J.; Marqués, R.; Medina, Francisco; Gómez Laso, Miguel Ángel Upna; Martín, F. (AIP Publishing, 2004)   Artículo / Artikulua  OpenAccess
      Transduction of magnetoinductive waves (MIWs) in planar technology is demonstrated. A transducer consisting of a one-dimensional periodic array of metallic split squared ring resonators (SSRR), placed between a pair of ...
    • Planoconcave lens by negative refraction of stacked subwavelength hole arrays 

      Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna; Sorolla Ayza, Mario Upna; Campillo, Igor (Optical Society of America, 2008)   Artículo / Artikulua  OpenAccess
      This work presents the design of a planoconcave parabolic negative index metamaterial lens operating at millimeter wavelengths fabricated by using stacked subwavelength hole arrays. A staircase approximation to the ideal ...
    • Polarization diversity scheme for BOTDA sensors based on a double orthogonal pump interaction 

      Urricelqui Polvorinos, Javier Upna; López Fernandino, Felipe; Sagüés García, Mikel Upna; Loayssa Lara, Alayn Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      We introduce a Brillouin optical time domain analysis (BOTDA) sensor deploying a novel polarization diversity technique based on the use of two orthogonal pump pulses which simultaneously interact with a phase modulated ...
    • Polarization selection with stacked hole array metamaterial 

      Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna; Sorolla Ayza, Mario Upna; Campillo, Igor (AIP Publishing, 2008)   Artículo / Artikulua  OpenAccess
      Polarization rotation or selection appears in materials with optical activity, or those with Faraday effect, or in liquid crystals. In this letter we present a structure, with an analogous response, using stacked ...
    • Polarization-tunable negative or positive refraction in self-complementariness-based extraordinary transmission prism 

      Navarro Cía, Miguel Upna; Beruete Díaz, Miguel Upna; Falcone Lanas, Francisco Javier Upna; Sorolla Ayza, Mario Upna (EMW Publishing, 2010)   Artículo / Artikulua  OpenAccess
      Here we report a prism made of stacked quasi-selfcomplementary extraordinary transmission surfaces which allows simultaneously left- and right-handed propagation within the V-band for vertical and horizontal polarizations, ...
    • Polarized left-handed extraordinary optical transmission of subterahertz waves 

      Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna; Sorolla Ayza, Mario Upna; Campillo, Igor (Optical Society of America, 2007)   Artículo / Artikulua  OpenAccess
      In this paper we design and measure a metamaterial polarizing device working in the sub-terahertz range. The polarizer is based on a modified version of our previous miniaturized Stacked Hole Array (SHA) structure, an ...
    • Polypropylene-substrate-based SRR- and CSRR-metasurfaces for submillimeter waves 

      Aznabet, Mariem; Navarro Cía, Miguel Upna; Kuznetsov, Sergei A.; Gelfand, A. V.; Fedorinina, N. I.; Goncharov, Yu. G.; Beruete Díaz, Miguel Upna; El Mrabet, O.; Sorolla Ayza, Mario Upna (Optical Society of America, 2008)   Artículo / Artikulua  OpenAccess
      In this paper it is presented the fabrication of low loss millimeter wave metamaterials based on patterning on polypropylene substrates by conventional contact photolitography. We study numerically and experimentally ...
    • Producing and exploiting simultaneously the forward and backward coupling in EBG-assisted microstrip coupled lines 

      Percaz Ciriza, Jon Mikel Upna; Chudzik, Magdalena Upna; Arnedo Gil, Israel Upna; Arregui Padilla, Iván Upna; Teberio Berdún, Fernando Upna; Gómez Laso, Miguel Ángel Upna; Lopetegui Beregaña, José María Upna (IEEE, 2016)   Artículo / Artikulua  OpenAccess
      In this paper, a methodology is proposed for the design of EBG-assisted coupled line structures in microstrip technology, controlling independently the forward and backward coupling. It is based on the use of a ...
    • Pyridine vapors detection by an optical fibre sensor 

      Elosúa Aguado, César Upna; Bariáin Aisa, Cándido Upna; Matías Maestro, Ignacio Upna; Rodríguez, Antonio; Colacio, Enrique; Salinas Castillo, Alfonso; Segura Carretero, Antonio; Fernández Gutiérrez, Alberto (MDPI, 2008)   Artículo / Artikulua  OpenAccess
      An optical fibre sensor has been implemented towards pyridine vapors detection; to achieve this, a novel vapochromic material has been used, which, in solid state, suffers a change in colour from blue to pink-white in ...
    • Radio characterization for ISM 2.4 GHz wireless sensor networks for judo monitoring applications 

      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, 2014)   Artículo / Artikulua  OpenAccess
      In this work, the characterization of the radio channel for ISM 2.4GHz Wireless Sensor Networks (WSNs) for judo applications is presented. The environments where judo activity is held are usually complex indoor scenarios ...