Now showing items 38-57 of 297

    • A comprehensive model for lithium-ion batteries: from the physical principles to an electrical model 

      Berrueta Irigoyen, Alberto; Urtasun Erburu, Andoni Upna; Ursúa Rubio, Alfredo Upna; Sanchis Gúrpide, Pablo Upna (Elsevier, 2018)   Artículo / Artikulua
      The growing interest in e-mobility and the increasing installation of renewable energy-based systems are leading to rapid improvements in lithium-ion batteries. In this context, battery manufacturers and engineers require ...
    • Control of a single-switch two-input buck converter for MPPT of two PV strings 

      Urtasun Erburu, Andoni Upna; Dah-Chuan Lu, Dylan (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      In this paper, the Two-Input Buck (TIBuck) converter is proposed as the DC/DC stage for photovoltaic (PV) cascaded converters. This converter is attractive for this application because it is cost-effective and reliable and ...
    • Control strategies to smooth short-term power fluctuations in large photovoltaic plants using battery storage systems 

      Marcos Álvarez, Javier Upna; Parra Laita, Íñigo de la Upna; García Solano, Miguel Upna; Marroyo Palomo, Luis Upna (MDPI, 2014)   Artículo / Artikulua  OpenAccess
      The variations in irradiance produced by changes in cloud cover can cause rapid fluctuations in the power generated by large photovoltaic (PV) plants. As the PV power share in the grid increases, such fluctuations may ...
    • Converging biconcave metallic lens by double-negative extraordinary transmission metamaterial 

      Navarro Cía, Miguel Upna; Beruete Díaz, Miguel Upna; Sorolla Ayza, Mario Upna; Campillo, Igor (AIP Publishing, 2009)   Artículo / Artikulua  OpenAccess
      In this letter we present simulation and experimental results of a left-handed converging biconcave metallic lens made of stacked subwavelength hole arrays SSHAs working in the millimeter wave range with additional ...
    • Cost-effective Brillouin optical time-domain analysis sensor using a single optical source and passive optical filtering 

      Iribas Pardo, Haritz Upna; Urricelqui Polvorinos, Javier Upna; Mariñelarena Ollacarizqueta, Jon Upna; Sagüés García, Mikel Upna; Loayssa Lara, Alayn Upna (Hindawi Publishing Corporation, 2016)   Artículo / Artikulua  OpenAccess
      We present a simplified configuration for distributed Brillouin optical time-domain analysis sensors that aims to reduce the cost of the sensor by reducing the number of components required for the generation of the two ...
    • Decoupling of multifrequency dipole antenna arrays for microwave imaging applications 

      Sáenz Sainz, Elena Upna; Guven, K.; Ozbay, Ekmel; Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna (Hindawi Publishing Corporation, 2010)   Artículo / Artikulua  OpenAccess
      The mutual coupling between elements of a multifrequency dipole antenna array is experimentally investigated by S-parameter measurements and planar near-field scanning of the radiated field. A multifrequency array with ...
    • Deposition of an overlay with electrostactic self-assembly method in long period fiber gratings 

      Del Villar, Ignacio Upna; Achaerandio, Miguel Upna; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna (Optical Society of America, 2005)   Artículo / Artikulua  OpenAccess
      It was proved that the deposition of an overlay material onto a long-period fiber grating causes important shifts in the wavelengths of the typical attenuation bands that are caused by coupling between cladding and core ...
    • Description of bow-tie nanoantennas excited by localized emitters using conformal transformation 

      Pacheco Peña, Víctor Upna; Beruete Díaz, Miguel Upna; Fernández Domínguez, Antonio I.; Luo, Yu; Navarro Cía, Miguel Upna (American Chemical Society, 2016)   Artículo / Artikulua  OpenAccess
      The unprecedented advance experienced by nano- fabrication techniques and plasmonics research over the past few years has made possible the realization of nanophotonic systems entering into the so-called strong coupling ...
    • Design and performance analysis of wireless body area networks in complex indoor e-Health hospital environments for patient remote monitoring 

      Aguirre Gallego, Erik Upna; López Iturri, Peio Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Rivarés Garasa, Carmen; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (SAGE, 2016)   Artículo / Artikulua  OpenAccess
      In this article, the design and performance analysis of wireless body area network–based systems for the transmission of medical information readable in an android-based application deployed within complex indoor e-Health ...
    • Design of beam-forming networks for scannable multi-beam antenna arrays using CORPS 

      Panduro, Marco A.; Río Bocio, Carlos del Upna (EMW Publishing, 2008)   Artículo / Artikulua  OpenAccess
      This paper deals with the design of beam-forming networks (BFN) for scannable multibeam antenna arrays using Coherently Radiating Periodic Structures (CORPS). This design of CORPS-BFN considers the optimization of the ...
    • Design of concentric ring antenna arrays for isoflux radiation in GEO satellites 

      Reyna, Alberto; Panduro, Marco A.; Río Bocio, Carlos del Upna (Institute of Electronics, Information and Communication Engineers (IEICE), 2011)   Artículo / Artikulua  OpenAccess
      The design of concentric rings arrays for isoflux radiation is reported in this paper. This design considers the reduction of the side lobe level and the isoflux radiation requirements for Geostationary Earth Orbit (GEO) ...
    • Design of MOS-translinear multiplier/dividers in analog VLSI 

      López Martín, Antonio Upna; Carlosena García, Alfonso Upna (Hindawi Publishing Corporation, 2000)   Artículo / Artikulua  OpenAccess
      A general framework for designing current-mode CMOS analog multiplier/divider circuits based on the cascade connection of a geometric-mean circuit and a squarer/ divider is presented. It is shown how both building blocks ...
    • Design of UAVs-based 3D antenna arrays for a maximum performance in terms of directivity and SLL 

      Garza, Jesús; Panduro, Marco A.; Reyna, Alberto; Romero, Gerardo; Río Bocio, Carlos del Upna (Hindawi, 2016)   Artículo / Artikulua  OpenAccess
      This paper presents a design of UAVs-based 3D antenna arrays for a maximum performance in terms of directivity and side lobe level (SLL). This paper illustrates how to model the UAVs formation flight using 3D nonuniform ...
    • Design rules for lossy mode resonance based sensors 

      Del Villar, Ignacio Upna; Hernáez Sáenz de Zaitigui, Miguel Upna; Ruiz Zamarreño, Carlos Upna; Sánchez Zábal, Pedro Upna; Fernández Valdivielso, Carlos Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (Optical Society of America, 2012)   Artículo / Artikulua  OpenAccess
      Lossy mode resonances can be obtained in the transmission spectrum of cladding removed multimode optical fiber coated with a thin-film. The sensitivity of these devices to changes in the properties of the coating or the ...
    • Development of a low mobility IEEE 802.15.4 compliant VANET system for urban environments 

      Nazábal Urriza, Juan Antonio Upna; Falcone Lanas, Francisco Javier Upna; Fernández Valdivielso, Carlos Upna; Matías Maestro, Ignacio Upna (MDPI, 2013)   Artículo / Artikulua  OpenAccess
      The use of Vehicular Ad-Hoc Networks (VANETs) is growing nowadays and it includes both roadside-to-vehicle communication (RVC) and inter-vehicle communication (IVC). The purpose of VANETs is to exchange useful information ...
    • Development of an in-fiber nanocavity towards detection of volatile organic gases 

      Elosúa Aguado, César Upna; Matías Maestro, Ignacio Upna; Bariáin Aisa, Cándido Upna; Arregui San Martín, Francisco Javier Upna (MDPI, 2006)   Artículo / Artikulua  OpenAccess
      A fiber optic sensor for Volatile Organic Compounds (VOCs) detection has been developed and characterized for some organic gasses. The sensor is based on a novel vapochromic material, which is able to change its optical ...
    • Development of an optical refractometer by analysis of one-dimensional photonic bandgap structures with defects 

      Matías Maestro, Ignacio Upna; Del Villar, Ignacio Upna; Arregui San Martín, Francisco Javier Upna (Optical Society of America, 2003)   Artículo / Artikulua  OpenAccess
      A theoretical analysis of an optical fiber photonic-bandgap-based refractometer is presented. The design is based on a quarter-wave ref lector with one defect. By modifying both the real and the imaginary parts of the index ...
    • Diffusive-light invisibility cloak for transient illumination 

      Orazbayev, Bakhtiyar Upna; Beruete Díaz, Miguel Upna; Martínez, Alejandro; García Meca, Carlos (American Physical Society, 2016)   Artículo / Artikulua  OpenAccess
      Invisibility in a diffusive-light-scattering medium has been recently demonstrated by employing a scattering-cancellation core-shell cloak. Unlike nondiffusive cloaks, such a device can be simultaneously macroscopic, ...
    • Dipolar resonances in conductive carbon micro-fibers probed by near-field terahertz spectroscopy 

      Khromova, Irina Upna; Navarro Cía, Miguel Upna; Brener, I.; Reno, J. L.; Ponomarev, A.; Mitrofanov, Oleg (AIP Publishing, 2015)   Artículo / Artikulua  OpenAccess
      We observe dipole resonances in thin conductive carbon micro-fibers by detecting an enhanced electric field in the near-field of a single fiber at terahertz (THz) frequencies. Time-domain analysis of the electric field ...
    • Dispersion properties of an elliptical patch with cross shaped aperture for synchronized propagation of transverse magnetic and electric surface waves 

      Tellechea Pereda, Amagoia Upna; Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna; Iriarte Galarregui, Juan Carlos Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      This paper presents a novel pixel geometry for the implementation of metasurfaces requiring synchronized phase propagation of transverse magnetic (TM) and transverse electric (TE) modes. The pixel is composed by an elliptical ...