Now showing items 279-298 of 298

    • Ultra-compact planoconcave zoned metallic lens based on the fishnet metamaterial 

      Pacheco-Peña, Víctor Upna; Orazbayev, Bakhtiyar Upna; Torres Landívar, Víctor Upna; Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna (AIP Publishing, 2013)   Artículo / Artikulua  OpenAccess
      A 1.5λ0 -thick planoconcave zoned lens based on the fishnet metamaterial is demonstrated experimentally at millimeter wavelengths. The zoning technique applied allows a volume reduction of 60% compared to a full fishnet ...
    • Ultra-long (290 km) remote interrogation sensor network based on a random distributed feedback fiber laser 

      Miguel Soto, Verónica de; Leandro González, Daniel Upna; López-Amo Sáinz, Manuel Upna (Optical Society of America, 2018)   Artículo / Artikulua  OpenAccess
      In this work, an interferometric sensor has been interrogated 290 km away from the monitoring station, reaching the longest distance in fiber optic sensing up to date. This has been attained by employing a double-pumped ...
    • Ultra-wide band corrugated profiled horn antenna design 

      Teniente Vallinas, Jorge Upna; Gonzalo García, Ramón Upna; Río Bocio, Carlos del Upna (IEEE, 2002)   Artículo / Artikulua  OpenAccess
      Nowadays, an increasing number of applications need stable radiation patterns with low sidelobes and low crosspolar levels in a very wide bandwidth. Gaussian Profiled Horn Antennas (GPHA’s) have demonstrated its feasibility ...
    • Ultra-wideband metamaterial filter based on electroinductive-wave coupling between microstrips 

      Navarro Cía, Miguel Upna; Carrasco, J.M.; Beruete Díaz, Miguel Upna; Falcone Lanas, Francisco Javier Upna (EMW Publishing, 2009)   Artículo / Artikulua  OpenAccess
      In this work, we analyse the frequency response of microstrip lines coupled by complementary split ring resonators (CSRRs) etched on the ground plane supporting electroinductive waves (EIWs). The single-particle ...
    • Ultrahigh-sensitivity sensors based on thin-film coated long period gratings with reduced diameter, in transition mode and near the dispersion turning point 

      Del Villar, Ignacio Upna (Optical Society of America, 2015)   Artículo / Artikulua  OpenAccess
      The mode transition and the dispersion turning point have been explored for optimization of thin-film coated long period fiber gratings during the last years. In this work and additional parameter, the cladding diameter, ...
    • Upper bounds on scattering processes and metamaterial-inspired structures that reach them 

      Ederra Urzainqui, Íñigo Upna; Liberal Olleta, Íñigo Upna; Gonzalo García, Ramón Upna; Ziolkowski, Richard W. (IEEE, 2014)   Artículo / Artikulua  OpenAccess
      The physical limitations on time-harmonic scattering processes are investigated on the basis of the optical theorem. Previously derived least upper bounds on the total scattering and absorption cross-sections are obtained ...
    • Vertically coupled microring resonators using one epitaxial growth step and single-side lithography 

      García López, Óscar; Thourhout, Dries Van; Lasaosa Medarde, Daniel; López-Amo Sáinz, Manuel Upna; Baets, Roel; Galarza Galarza, Marko (Optical Society of America, 2015)   Artículo / Artikulua  OpenAccess
      A new concept for the fabrication of integrated microring resonators, requiring only one single epitaxial growth and two single-side lithographic steps, is proposed in what is the simplest fabrication scheme for vertical ...
    • Vibration detection using optical fiber sensors 

      Rodríguez García, Yoany; Corres Sanz, Jesús María Upna; Goicoechea Fernández, Javier Upna (Hindawi, 2010)   Artículo / Artikulua  OpenAccess
      Condition monitoring of heavy electromechanical equipment is commonly accomplished in the industry using vibration analysis. Several techniques, mainly based on capacitive and piezoelectric accelerometers, have been applied ...
    • Vibrato in singing voice: the link between source-filter and sinusoidal models 

      Carlosena García, Alfonso Upna; Arroabarren Alemán, Ixone Upna (Springer Open, 2004)   Artículo / Artikulua  OpenAccess
      The application of inverse filtering techniques for high-quality singing voice analysis/synthesis is discussed. In the context of source-filter models, inverse filtering provides a noninvasive method to extract the voice ...
    • Volatile organic compound optical fiber sensors: a review 

      Elosúa Aguado, César Upna; Matías Maestro, Ignacio Upna; Bariáin Aisa, Cándido Upna; Arregui San Martín, Francisco Javier Upna (MDPI, 2006)   Artículo / Artikulua  OpenAccess
      Volatile organic compound (VOC) detection is a topic of growing interest with applications in diverse fields, ranging from environmental uses to the food or chemical industries. Optical fiber VOC sensors offering new and ...
    • Wavelength and phase detection based SMS fiber sensors optimized with etching and nanodeposition 

      Cardona-Maya, Yamile; Del Villar, Ignacio Upna; Socorro Leránoz, Abián Bentor Upna; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna; Botero-Cadavid, Juan F. (IEEE, 2016)   Artículo / Artikulua  OpenAccess
      The development of an optical fiber refractometer by hydrogen fluoride etching and sputtering deposition of a thin-film of indium tin oxide on a single-mode-multimode-single-mode fiber structure has been analyzed with ...
    • WDM bi-directional transmission over 35 km amplified fiber-optic bus network using Raman amplification for optical sensors 

      Díaz Lucas, Silvia Upna; Lasheras, Gorka; López-Amo Sáinz, Manuel Upna (Optical Society of America, 2005)   Artículo / Artikulua  OpenAccess
      We demonstrate a novel distributed fiber Raman amplified bus topology used for WDM transmission over 35 km of single-mode fiber by use of a multiwavelength Raman pump laser and eight Fiber Bragg gratings (FBGs). This ...
    • Wide angle terahertz sensing with a cross-dipole frequency selective surface 

      Rodríguez Ulibarri, Pablo Upna; Kuznetsov, Sergei A.; Beruete Díaz, Miguel Upna (AIP Publishing, 2016)   Artículo / Artikulua  OpenAccess
      In this work, a terahertz sensor based on a cross dipole frequency selective surface is analyzed and experimentally tested. The sensing structure is optimized for operation at the fundamental band- stop resonance near ...
    • 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 ...
    • Wideband channel modeling for mm-wave inside trains for 5G-related applications 

      Moreno García-Loygorri, Juan; Briso Rodríguez, César; Arnedo Gil, Israel Upna; Calvo, César; Gómez Laso, Miguel Ángel Upna; He, Danping; Jiménez, Florentino; González Posadas, Vicente (Hindawi / Wiley, 2018)   Artículo / Artikulua  OpenAccess
      Passenger trains and especially metro trains have been identified as one of the key scenarios for 5G deployments. The wireless channel inside a train car is reported in the frequency range between 26.5GHz and 40GHz. These ...
    • Wideband unidirectional transmission with tunable sign-switchable refraction and deflection in nonsymmetric structures 

      Rodríguez Ulibarri, Pablo Upna; Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna; Serebryannikov, Andriy E. (American Physical Society, 2013)   Artículo / Artikulua  OpenAccess
      A general theory of reciprocal unidirectional transmission with tunable sign-switchable refraction and deflection of outgoing wave in structures with broken spatial inversion symmetry is presented. Several coupling scenarios ...
    • Wood zone plate fishnet metalens 

      Orazbayev, Bakhtiyar Upna; Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna (EDP Sciences, 2015)   Artículo / Artikulua  OpenAccess
      Fresnel-zone plate lenses provide focusing performance while having low profile. Unfortunately, they usually display higher reflection losses than conventional dielectric lenses. Here, we demonstrate a low-profile Wood ...
    • Zoned fishnet lens antenna with reference phase for side lobe reduction 

      Pacheco-Peña, Víctor Upna; Navarro Cía, Miguel Upna; Orazbayev, Bakhtiyar Upna; Minin, Igor V.; Minin, Oleg V.; Beruete Díaz, Miguel Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      Reduction of first side lobe level and nulls in artificial fishnet metalenses is accomplished here by applying the reference phase concept along with the zoning technique. Higher focusing efficiency is achieved for a ...
    • Zoned near-zero refractive index fishnet lens antenna: steering millimeter waves 

      Pacheco-Peña, Víctor Upna; Orazbayev, Bakhtiyar Upna; Beaskoetxea Gartzia, Unai Upna; Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna (AIP Publishing, 2014)   Artículo / Artikulua  OpenAccess
      A zoned fishnet metamaterial lens is designed, fabricated, and experimentally demonstrated at millimeter wavelengths to work as a negative near-zero refractive index lens suitable for compact lens antenna configurations. ...
    • ε-near-zero (ENZ) graded index quasi-optical devices: steering and splitting millimeter waves 

      Pacheco-Peña, Víctor Upna; Torres Landívar, Víctor Upna; Beruete Díaz, Miguel Upna; Navarro Cía, Miguel Upna; Engheta, Nader (IOP Publishing, 2014)   Artículo / Artikulua  OpenAccess
      Graded index ε near-zero (GRIN-ENZ) quasi-optical components such as beam steerers and power splitters are designed, simulated and analyzed. The GRIN-ENZ medium is realized using stacked narrow hollow waveguides whose ...