Now showing items 27-36 of 36

    • A simplified design inline microstrip-to-waveguide transition 

      Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna; Pérez Escudero, José Manuel Upna; Torres García, Alicia E. Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      A simplified design of an inline transition between microstrip and rectangular waveguide is presented in this paper. The transition makes use of a dielectric filled rectangular waveguide (DFRW) as an intermediate step, ...
    • Steering surface plasmons with a graded index dielectric medium 

      Beruete Díaz, Miguel Upna; Pacheco-Peña, Víctor Upna (IOP Publishing, 2018)   Artículo / Artikulua  OpenAccess
      The arbitrary control of surface plasmon (SP) propagation has become an intense research topic for several decades. This is due to the fact that they can be used in a variety of fields such as optical trapping, nanoantennas ...
    • Strong angular dependence of resonant states in 2D dielectric cylinder rings 

      Andueza Unanua, Ángel María; Pérez Conde, Jesús Upna; Sevilla Moróder, Joaquín Upna (AIP Publishing, 2018)   Artículo / Artikulua
      We investigate collective resonators made of dielectric cylinders assembled as two-dimensional regular octagons and decagons. These structures exhibit collective resonance states that change their intensity with the incident ...
    • Study on isolation improvement between closely-packed patch antenna arrays based on fractal metamaterial electromagnetic bandgap structures 

      Alibakhshikenari, Mohammad; Virdee, Bal S.; See, Chan H.; Abd-Alhameed, Raed; Ali, Abdul; Hussein Ali, Ammar; Falcone Lanas, Francisco Javier Upna; Limiti, Ernesto (Institution of Engineering and Technology, 2018)   Artículo / Artikulua  OpenAccess
      A decoupling metamaterial (MTM) configuration based on fractal electromagnetic-bandgap (EMBG) structure is shown to significantly enhance isolation between transmitting and receiving antenna elements in a closely-packed ...
    • Super class AB RFC OTA with adaptive local common-mode feedback 

      Garde Luque, María Pilar; López Martín, Antonio Upna; Carvajal, Ramón G.; Ramírez-Angulo, J. (Institution of Engineering and Technology, 2018)   Artículo / Artikulua  OpenAccess
      A super class AB recycling folded cascode operational transconductance amplifier is presented. It employs local common-mode feedback using two matched tuneable active resistors, allowing to adapt the amplifier to different ...
    • Supercapacitors: electrical characteristics, modelling, applications and future trends 

      Berrueta Irigoyen, Alberto; Ursúa Rubio, Alfredo Upna; San Martín Biurrun, Idoia Upna; Eftekhari, Ali; Sanchís Gúrpide, Pablo Upna (IEEE, 2019)   Artículo / Artikulua  OpenAccess
      Energy storage systems are playing an increasingly important role in a variety of applications, such as electric vehicles or grid-connected systems. In this context, supercapacitors (SCs) are gaining ground due to their ...
    • THz sensing with anomalous extraordinary optical transmission hole arrays 

      Jáuregui López, Irati; Rodríguez Ulibarri, Pablo Upna; Kuznetsov, Sergei A.; Nikolaev, Nazar A.; Beruete Díaz, Miguel Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      Subwavelength hole array (HA) metasurfaces support the so-called extraordinary optical transmission (EOT) resonance that has already been exploited for sensing. In this work, we demonstrate the superior performance of a ...
    • Virtual FBGs using saturable absorbers for sensing with fiber lasers 

      Rodríguez Cobo, L.; Pérez Herrera, Rosa Ana Upna; Quintela, M. A.; Ruiz Lombera, Rubén; López-Amo Sáinz, Manuel Upna; López Higuera, José Miguel (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      The spectral narrowing of Fiber Bragg Gratings (FBGs) introduced by unpumped Er-doped fiber (EDF) was analyzed for fiber lasers (FL). Owing to spatial hole burning (SHB), the spectral response of a virtual FBG can be ...
    • A water content continuous monitoring of grapevine xylem tissue using a portable low-power cost-effective FMCW radar 

      Quemada, Carlos; García González, Cebrián; Iriarte Galarregui, Juan Carlos Upna; Marín Ederra, Diana; Gastón Beraza, Diego; Miranda Jiménez, Carlos Upna; Gonzalo García, Ramón Upna; Maestrojuán Biurrun, Itziar Upna; Santesteban García, Gonzaga Upna; Ederra Urzainqui, Íñigo Upna (IEEE, 2019)   Artículo / Artikulua
      This paper presents the real-time monitoring of a grapevine’s water content that flows up through the xylem tissue by means of a frequency-modulated continuous-wave (FMCW) radar. The application of an optimization process, ...
    • Watt-level green random laser at 532  nm by SHG of Yb-doped fiber laser 

      Rota Rodrigo, Sergio Upna; Gouhier, B.; Dixneuf, C.; Antoni Micollier, L.; Guiraud, G.; Leandro González, Daniel Upna; López-Amo Sáinz, Manuel Upna; Traynor, N.; Santarelli, G. (Optical Society of America, 2018)   Artículo / Artikulua  OpenAccess
      We have developed a Watt-level random laser at 532 nm. The laser is based on a 1064 nm random distributed ytterbium-gain assisted fiber laser seed with a 0.35 nm line-width and 900 mW polarized output power. A study for ...