• Single-longitudinal-mode dual wavelength-switchable fiber laser based on superposed fiber bragg gratings 

      Pérez Herrera, Rosa Ana Upna; Rodriguez-Cobo, L.; Quintela, M. A.; López Higuera, José Miguel; López-Amo Sáinz, Manuel Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      n this work, a simple switchable dual-wavelength short-cavity fiber laser operating in a single-longitudinal-mode regime at room temperature and based on superposed fiber Bragg gratings is proposed and experimentally ...
    • A slow light fishnet-like absorber in the millimeter-wave range 

      Navarro Cía, Miguel Upna; Torres Landívar, Víctor Upna; Beruete Díaz, Miguel Upna; Sorolla Ayza, Mario Upna (EMW Publishing, 2011)   Artículo / Artikulua  OpenAccess
      A novel route to achieve a narrowband free-space electromagnetic absorber in any range of the spectrum based on stacked subwavelength hole arrays is proposed. The absorption is obtained by means of a slow light mode inside ...
    • Small wind turbines sensorless MPPT: robustness analysis and lossless approach 

      Urtasun Erburu, Andoni Upna; Sanchis Gúrpide, Pablo Upna; Marroyo Palomo, Luis Upna (IEEE, 2014)   Artículo / Artikulua  OpenAccess
      The configuration Permanent Magnet Synchronous Generator (PMSG) with diode bridge is frequently used in small Wind Energy Conversion Systems (WESC) thanks to its reliability and low cost. In order to perform a sensorless ...
    • Soret fishnet metalens antenna 

      Orazbayev, Bakhtiyar Upna; Beruete Díaz, Miguel Upna; Pacheco Peña, Víctor Upna; Crespo López, Gonzalo; Teniente Vallinas, Jorge Upna; Navarro Cía, Miguel Upna (Springer Nature, 2015)   Artículo / Artikulua  OpenAccess
      At the expense of frequency narrowing, binary amplitude-only diffractive optical elements emulate refractive lenses without the need of large profiles. Unfortunately, they also present larger Fresnel reflection loss ...
    • 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 ...
    • Spectral evolution with incremental nanocoating of long period fiber gratings 

      Del Villar, Ignacio Upna; Corres Sanz, Jesús María Upna; Achaerandio, Miguel Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (Optical Society of America, 2006)   Artículo / Artikulua  OpenAccess
      The incremental deposition of a thin overlay on the cladding of a long-period fiber grating (LPFG) induces important resonance wavelength shifts in the transmission spectrum. The phenomenon is proved theoretically with ...
    • Split ring resonator-based left-handed coplanar waveguide 

      Martín, F.; Bonache, J.; Falcone Lanas, Francisco Javier Upna; Sorolla Ayza, Mario Upna; Marqués, R. (AIP Publishing, 2003)   Artículo / Artikulua  OpenAccess
      In this letter, a planar left-handed propagating medium consisting of a coplanar waveguide (CPW) inductively coupled to split ring resonators (SRR) and periodically loaded with narrow metallic wires is proposed. The wires ...
    • State-of-charge-based droop control for stand-alone AC supply systems with distributed energy storage 

      Urtasun Erburu, Andoni Upna; Sanchis Gúrpide, Pablo Upna; Marroyo Palomo, Luis Upna (Elsevier, 2015)   Artículo / Artikulua  OpenAccess
      The droop method is an advantageous technique for stand-alone AC supply systems, allowing for power sharing among various inverters with no need for communication cables. However, in stand-alone systems with multiple ...
    • A stopband filter design using a 1-D non-periodic defected ground structure 

      Garde Irigoyen, Ieltxu Aitor Upna; Río Bocio, Carlos del Upna (Wiley, 2003)   Artículo / Artikulua  OpenAccess
      The one-dimensional (1-D) defected ground structure is used to control the cutoff frequency characteristic. In this paper three non-periodic filters are built, in order to show the versatility of the DGS. Five unit cells ...
    • Strategies for fabrication of hydrogen peroxide sensors based on electrostatic self-assembly (ESA) method 

      Del Villar, Ignacio Upna; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Echeverría Morrás, Jesús Upna; Claus, Richard O. (Elsevier, 2004)   Artículo / Artikulua  OpenAccess
      An optical fiber sensor has been fabricated for detection of 5 M–0.1mM concentrations of hydrogen peroxide with a linear response. The deposition method used is electrostatic self-assembly (ESA) of polymer cationic and ...
    • Strong lateral displacement in polarization anisotropic extraordinary transmission metamaterial 

      Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna; Sorolla Ayza, Mario Upna (IOP Publishing Ltd, 2010)   Artículo / Artikulua  OpenAccess
      In this paper, a deep numerical as well as experimental study of the anisotropy response of extraordinary transmission metamaterials constructed by stacking subwavelength hole arrays is presented. Two-dimensional (2D) ...
    • Study and optimization of self-assembled polymeric multilayer structures with neutral red for pH sensing applications 

      Goicoechea Fernández, Javier Upna; Arregui San Martín, Francisco Javier Upna; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (Hindawi / Wiley, 2008)   Artículo / Artikulua  OpenAccess
      The characterization of nanostructured thin films is critical in the design and fabrication of optical sensors. Particularly, this work is a detailed study of the properties of layer-by-layer electrostatic self-assembled ...
    • 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 ...
    • Superbackscattering antenna arrays 

      Liberal Olleta, Íñigo Upna; Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna; Ziolkowski, Richard W. (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      This article discusses the theory, design and practical implementation of superbackscattering antenna arrays. In analogy with Uzkov’s maximal directivity theorem, it is demonstrated that the maximal backscattering ...
    • Surface waves of finite size electromagnetic band gap woodpile structures 

      Ederra Urzainqui, Íñigo Upna; Iriarte Galarregui, Juan Carlos Upna; Gonzalo García, Ramón Upna (EMW Publishing, 2011)   Artículo / Artikulua  OpenAccess
      This paper studies the surface modes at the interface of finite size Electromagnetic Band Gap (EBG) woodpile structures. The impact of different types of woodpile terminations on the properties of these surface modes is ...
    • Suspended-core fiber Sagnac combined dual-random mirror Raman fiber laser 

      Rodrigues Pinto, Ana Margarida Upna; Bravo Acha, Mikel Upna; Fernández Vallejo, Montserrat Upna; López-Amo Sáinz, Manuel Upna; Kobelke, J.; Schuster, K. (Optical Society of America, 2011)   Artículo / Artikulua  OpenAccess
      In the present work, a multiwavelength fiber laser based in the combination of a double-random mirror and a suspended-core Sagnac interferometer is presented. The double-random mirror acts by itself as a random laser, ...
    • Swept optical single sideband modulation for spectral measurement applications using stimulated Brillouin scattering 

      Sagüés García, Mikel Upna; Loayssa Lara, Alayn Upna (Optical Society of America, 2010)   Artículo / Artikulua  OpenAccess
      We propose a technique for the generation of broadband optical single sideband modulated signals. The technique is based on optically processing an optical double sideband signal using stimulated Brillouin scattering effect. ...
    • Synthesis of Brillouin frequency shift profiles to compensate non-local effects and Brillouin induced noise in BOTDA sensors 

      Urricelqui Polvorinos, Javier Upna; Sagüés García, Mikel Upna; Loayssa Lara, Alayn Upna (Optical Society of America, 2014)   Artículo / Artikulua  OpenAccess
      We present a novel technique for Brillouin optical time domain analysis (BOTDA) sensors that simultaneously compensates non local effects and reduces Brillouin noise. The technique relies on the wavelength modulation of ...
    • 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., ...
    • Synthesis of volumetric ring antenna array for terrestrial coverage pattern 

      Reyna, Alberto; Panduro, Marco A.; Río Bocio, Carlos del Upna (Hindawi, 2014)   Artículo / Artikulua  OpenAccess
      This paper presents a synthesis of a volumetric ring antenna array for a terrestrial coverage pattern. This synthesis regards the spacing among the rings on the planes X -Y, the positions of the rings on the plane X -Z, ...