• 3D-printed 96 GHz bull’s-eye antenna with off-axis beaming 

      Beaskoetxea Gartzia, Unai Upna; Maci, Stefano; Navarro Cía, Miguel Upna; Beruete Díaz, Miguel Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      Reducing the profile, footprint and weight of antennas embarked on aircrafts, drones or satellites has been a long pursued objective. Here we tackle this issue by developing a millimeter-wave 96 GHz elliptical Bull’s-Eye ...
    • 77-GHz high-gain bull’s-eye antenna with sinusoidal profile 

      Beaskoetxea Gartzia, Unai Upna; Pacheco Peña, Víctor Upna; Orazbayev, Bakhtiyar Upna; Akalin, Tahsin; Maci, Stefano; Navarro Cía, Miguel Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      A high-gain Bull’s-Eye leaky-wave horn antenna working at 77 GHz with sinusoidal profile has been designed, fabricated, and experimentally measured. The influence of the number of periods on the gain and beamwidth is ...
    • Accurate circuit modeling of fishnet structures for negative-index-medium applications 

      Torres Landívar, Víctor Upna; Mesa, Francisco; Navarro Cía, Miguel Upna; Rodríguez Berral, Raúl; Beruete Díaz, Miguel Upna; Medina, Francisco (IEEE, 2016)   Artículo / Artikulua  OpenAccess
      Metallic plates with a two-dimensional (2D) periodic distribution of sub-wavelength apertures are known to exhibit extraordinary transmission of electromagnetic waves. Stacking two or more of such plates gives place to the ...
    • 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 ...
    • All-dielectric periodic terajet waveguide using an array of coupled cuboids 

      Minin, Igor V.; Minin, Oleg V.; Pacheco Peña, Víctor Upna; Beruete Díaz, Miguel Upna (AIP Publishing, 2015)   Artículo / Artikulua  OpenAccess
      In this paper, the recently proposed technique to produce photonic jets (terajets at terahertz (THz) frequencies) using 3D dielectric cuboids is applied in the design of a mesoscale cuboid-chain wave- guide. The chains are ...
    • Analysis and description of HOLTIN service provision for AECG monitoring in complex indoor environments 

      Led Ramos, Santiago Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Aguirre Gallego, Erik Upna; Martínez de Espronceda Cámara, Miguel Upna; Serrano Arriezu, Luis Javier Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2013)   Artículo / Artikulua  OpenAccess
      In this work, a novel ambulatory ECG monitoring device developed in-house called HOLTIN is analyzed when operating in complex indoor scenarios. The HOLTIN system is described, from the technological platform level to its ...
    • Analysis matrix for smart cities 

      Branchi, Pablo Emilio; Fernández Valdivielso, Carlos Upna; Matías Maestro, Ignacio Upna (MDPI, 2014)   Artículo / Artikulua  OpenAccess
      The current digital revolution has ignited the evolution of communications grids and the development of new schemes for productive systems. Traditional technologic scenarios have been challenged, and Smart Cities have ...
    • Analysis of one-dimensional photonic band gap structures with a liquid crystal defect towards development of fiber-optic tunable wavelength filters 

      Del Villar, Ignacio Upna; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Claus, Richard O. (Optical Society of America, 2003)   Artículo / Artikulua  OpenAccess
      A theoretical analysis of a fiber optical photonic band gap based tunable wavelength filter is presented. The design presented here is based on the quarter wave reflector with a liquid crystal defect layer in the middle ...
    • Analysis of radio wave propagation for ISM 2.4 GHz wireless sensor networks in inhomogeneous vegetation environments 

      Azpilicueta Fernández de las Heras, Leyre Upna; López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Mateo Zozaya, Ignacio; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2014)   Artículo / Artikulua  OpenAccess
      The use of wireless networks has experienced exponential growth due to the improvements in terms of battery life and low consumption of the devices. However, it is compulsory to conduct previous radio propagation analysis ...
    • Analysis of wireless sensor network topology and estimation of optimal network deployment by deterministic radio channel characterization 

      Aguirre Gallego, Erik Upna; López Iturri, Peio Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2015)   Artículo / Artikulua  OpenAccess
      One of the main challenges in the implementation and design of context-aware scenarios is the adequate deployment strategy for Wireless Sensor Networks (WSNs), mainly due to the strong dependence of the radiofrequency ...
    • Annular apertures in metallic screens as extraordinary transmission and frequency selective surface structures 

      Rodríguez Ulibarri, Pablo Upna; Navarro Cía, Miguel Upna; Rodríguez Berral, Raúl; Mesa, Francisco; Medina, Francisco; Beruete Díaz, Miguel Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      A 2-D periodic array of annular apertures (or ring slots) is studied using an accurate circuit model. The model accounts for distributed and dynamic effects associated with the excitation of high-order modes operating above ...
    • An antibacterial coating based on a polymer/sol-gel hybrid matrix loaded with silver nanoparticles 

      Rivero Fuente, Pedro José Upna; Urrutia Azcona, Aitor Upna; Goicoechea Fernández, Javier Upna; Ruiz Zamarreño, Carlos Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (Springer, 2011)   Artículo / Artikulua  OpenAccess
      In this work a novel antibacterial surface composed of an organic-inorganic hybrid matrix of tetraorthosilicate and a polyelectrolyte is presented. A precursor solution of tetraethoxysilane (TEOS) and poly(acrylic acid ...
    • Application of gold complexes in the development of sensors for volatile organic compounds 

      Luquin, Asunción Upna; Elosúa Aguado, César Upna; Vergara, Elena; Estella, Juncal Upna; Cerrada, Elena; Bariáin Aisa, Cándido Upna; Matías Maestro, Ignacio Upna; Garrido Segovia, Julián José Upna; Laguna, Mariano (World Gold Council, 2007)   Artículo / Artikulua  OpenAccess
      Two different kinds of sensors have been developed by using the same kind of vapochromic complexes. The vapochromic materials [Au2Ag2(C6F5)(4)L-2](n) have different colours depending on the ligand L. These materials change, ...
    • Application of remote power-by-light switching in a simplified BOTDA sensor network 

      Bravo Acha, Mikel Upna; Zornoza Indart, Ander; Loayssa Lara, Alayn Upna; López-Amo Sáinz, Manuel Upna; López Higuera, José Miguel; Ullán Nieto, Angel (MDPI, 2013)   Artículo / Artikulua  OpenAccess
      We propose and demonstrate the use of spatial multiplexing as a means to reduce the costs of distributed sensing networks. We propose a new scheme in which remote power-by-light switching is deployed to scan multiple ...
    • Arc-induced long period fiber gratings in the dispersion turning points 

      Colaço, Celso; Caldas, Paulo; Del Villar, Ignacio Upna; Chibante, Rui; Rego, Gaspar (IEEEOptical Society of America, 2016)   Artículo / Artikulua  OpenAccess
      We demonstrated the possibility to inscribe longperiod fiber gratings (LPFGs) in a B/Ge codoped fiber by using grating periods shorter than 150 μm. We also have arc-induced in the SMF 28 fiber an LPFG in the dispersion ...
    • Astronomical component estimation (ACE v.1) by time-variant sinusoidal modeling 

      Sinnesael, Matthias; Zivanovic, Miroslav Upna; Vleeschouwer, David De; Claeys, Philippe; Schoukens, Johan (Copernicus Publications, 2016)   Artículo / Artikulua  OpenAccess
      Accurately deciphering periodic variations in paleoclimate proxy signals is essential for cyclostratigraphy. Classical spectral analysis often relies on methods based on (fast) Fourier transformation. This technique has ...
    • BOTDA measurements tolerant to non-local effects by using a phase-modulated probe wave and RF demodulation 

      Urricelqui Polvorinos, Javier Upna; Sagüés García, Mikel Upna; Loayssa Lara, Alayn Upna (Optical Society of America, 2013)   Artículo / Artikulua  OpenAccess
      We demonstrate a Brillouin optical time domain analysis sensor based on a phase modulated probe wave and RF demodulation that provides measurements tolerant to frequency dependent variations of the pump pulse power induced ...
    • Brillouin optical time-domain analysis sensor assisted by Brillouin distributed amplification of pump pulses 

      Urricelqui Polvorinos, Javier Upna; Sagüés García, Mikel Upna; Loayssa Lara, Alayn Upna (Optical Society of America, 2015)   Artículo / Artikulua  OpenAccess
      We demonstrate the extension of the measurement range of Brillouin optical time-domain analysis (BOTDA) sensors using a distributed Brillouin amplifier (DBA). The technique is based on injecting a DBA pump wave in the ...
    • Brillouin optical time-domain analysis sensor with pump pulse amplification 

      Mompó Roselló, Juan José Upna; Urricelqui Polvorinos, Javier Upna; Loayssa Lara, Alayn Upna (Optical Society of America, 2016)   Artículo / Artikulua  OpenAccess
      We demonstrate a simple technique to provide conventional Brillouin optical time-domain analysis sensors with mitigation for pump pulse attenuation. The technique is based on operating the sensor in loss configuration so ...
    • Broadband frequency and angular response of a sinusoidal bull’s eye antenna 

      Beaskoetxea Gartzia, Unai Upna; Navarro Cía, Miguel Upna; Beruete Díaz, Miguel Upna (IOP Publishing, 2016)   Artículo / Artikulua  OpenAccess
      A thorough experimental study of the frequency and beaming angle response of a metallic leaky-wave bull’s eye antenna working at 77 GHz with a sinusoidally corrugated profile is presented. The beam scanning property of ...