Envíos recientes

  • 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 ...
  • 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 ...
  • Geometry influence on the transmission spectra of dielectric single layers of spheres with different compactness 

    Andueza Unanua, Ángel María; Echeverría, R.; Morales Zimmermann, Paola Andrea Upna; Sevilla Moróder, Joaquín Upna (AIP Publishing, 2010)   Artículo / Artikulua  OpenAccess
    The transmission of spectra of different dielectric spheres single layer arrangements has been measured. High dielectric permittivity ε =7 spheres of several millimeters of diameter were used to build the samples whose ...
  • Transmission spectra changes produced by decreasing compactness of opal-like structures 

    Andueza Unanua, Ángel María; Echeverría, R.; Morales Zimmermann, Paola Andrea Upna; Sevilla Moróder, Joaquín Upna (AIP Publishing, 2009)   Artículo / Artikulua  OpenAccess
    Artificial opal-like structures based on spheres and colloidal particles have been fabricated in a controlled way, presenting optical band-gap properties in the optical frequency range. Nonclose packed artificial opals ...
  • 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 ...
  • Split ring resonator-based left-handed coplanar waveguide 

    Martı́n, 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 ...
  • Routing with classical corrugated waveguide low-pass filters with embedded bends 

    Teberio Berdún, Fernando Upna; Percaz Ciriza, Jon Mikel Upna; Arregui Padilla, Iván Upna; Martín Iglesias, Petronilo; Lopetegui Beregaña, José María Upna; Gómez Laso, Miguel Ángel Upna; Arnedo Gil, Israel Upna (EMW Publishing, 2018)   Artículo / Artikulua  OpenAccess
    A very simple design method to embed routing capabilities in classical corrugated filters is presented in this paper. The method is based on the calculation of the heights and lengths of the so-called filters design ...
  • Resonant quasi-periodic structure for rectangular waveguide technology with wide stopband and band-pass behavior 

    Arregui Padilla, Iván Upna; Teberio Berdún, Fernando Upna; Arnedo Gil, Israel Upna; Percaz Ciriza, Jon Mikel Upna; Gómez Torrent, Adrián Upna; Chudzik, Magdalena Upna; Gómez Laso, Miguel Ángel Upna; Lopetegui Beregaña, José María Upna (EMW Publishing, 2016)   Artículo / Artikulua  OpenAccess
    In this paper, a novel quasi-periodic structure for rectangular waveguide technology is proposed. The constituent unit cells of the structure feature a resonant behavior, providing high attenuation levels in the stopband ...
  • Parameter-independent control for battery chargers based on virtual impedance emulation 

    Urtasun Erburu, Andoni Upna; Berrueta Irigoyen, Alberto; Sanchís 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 ...
  • 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; Sanchís 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 ...
  • Rectangular waveguide filters with meandered topology 

    Teberio Berdún, Fernando Upna; Percaz Ciriza, Jon Mikel Upna; Arregui Padilla, Iván Upna; Martín Iglesias, Petronilo; Lopetegui Beregaña, José María Upna; Gómez Laso, Miguel Ángel Upna; Arnedo Gil, Israel Upna (IEEE, 2018)   Artículo / Artikulua
    In this paper, a new topology for rectangular waveguide bandpass and low-pass filters is presented. A simple, accurate, and robust design technique for these novel meandered waveguide filters is provided. The proposed ...
  • State-of-charge-based droop control for stand-alone AC supply systems with distributed energy storage 

    Urtasun Erburu, Andoni Upna; Sanchís 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 ...
  • 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 ...
  • High frequency power transformers with foil windings: maximum interleaving and optimal design 

    Barrios Rípodas, Ernesto Upna; Urtasun Erburu, Andoni Upna; Ursúa Rubio, Alfredo Upna; Marroyo Palomo, Luis Upna; Sanchís Gúrpide, Pablo Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
    Foil conductors and primary and secondary interleaving are normally used to minimize winding losses in high frequency transformers used for high-current power applications. However, winding interleaving complicates the ...
  • Frequency-based energy management strategy for stand-alone systems with distributed battery storage 

    Urtasun Erburu, Andoni Upna; Barrios Rípodas, Ernesto Upna; Sanchís Gúrpide, Pablo Upna; Marroyo Palomo, Luis Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
    Distributed generation is an attractive solution for stand-alone AC supply systems. In such systems, the installation of two or more energy-storage units is recommended for system redundancy and may also be required when ...
  • Energy management strategy for a battery-diesel stand-alone system with distributed PV generation based on grid frequency modulation 

    Urtasun Erburu, Andoni Upna; Sanchís Gúrpide, Pablo Upna; Barricarte Rivas, David; Marroyo Palomo, Luis Upna (Elsevier, 2014)   Artículo / Artikulua  OpenAccess
    A hybrid PV-Battery-Diesel configuration is very attractive for stand-alone systems in terms of cost and reliability. In many applications, the battery and the diesel generator are centralized and generate the AC grid while ...
  • Small wind turbines sensorless MPPT: robustness analysis and lossless approach 

    Urtasun Erburu, Andoni Upna; Sanchís 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 ...
  • Modeling of small wind turbines based on PMSG with diode bridge for sensorless maximum power tracking 

    Urtasun Erburu, Andoni Upna; Sanchís Gúrpide, Pablo Upna; San Martín Biurrun, Idoia Upna; López Taberna, Jesús; Marroyo Palomo, Luis Upna (Elsevier, 2013)   Artículo / Artikulua  OpenAccess
    The Permanent Magnet Synchronous Generator (PMSG) with diode bridge is frequently used in small Wind Energy Conversion Systems (WECS). This configuration is robust and cheap, and therefore suitable for small WECS. In order ...
  • Fabrication of Bragg gratings on the end facet of standard optical fibers by sputtering the same material 

    Ascorbe Muruzabal, Joaquín Upna; Corres Sanz, Jesús María Upna; del Villar, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (IEEE, 2016)   Artículo / Artikulua  OpenAccess
    A sputtering process has been applied to deposit quarter-wavelength stacks on the end facet of cleaved optical fibers by using only one sputtering target. Standard multimode optical fibers were used as substrates to fabricate ...
  • Adaptive voltage control of the DC/DC boost stage in PV converters with small input capacitor 

    Urtasun Erburu, Andoni Upna; Sanchís Gúrpide, Pablo Upna; Marroyo Palomo, Luis Upna (IEEE, 2013)   Artículo / Artikulua  OpenAccess
    In the case of photovoltaic (PV) systems, an adequate PV voltage regulation is fundamental in order to both maximize and limit the power. For this purpose, a large input capacitor has traditionally been used. However, when ...

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