• Ku band low profile asymmetric Bull’s-Eye antenna with reduced side lobes and monopole feeding 

      Beaskoetxea Gartzia, Unai Upna; Torres García, Alicia E.; Beruete Díaz, Miguel Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      In this paper, a linearly polarized low profile and asymmetric Bull’s-Eye leaky wave antenna fed by a monopole operating at 13 GHz is presented. Broadside radiation from the monopole is achieved by surrounding it with an ...
    • Optimized strain long-period fiber grating (LPFG) sensors operating at the dispersion turning point 

      Del Villar, Ignacio; Fuentes, Omar; Chiavaioli, Francesco; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      Two phenomena for enhancing the sensitivity of longperiod fiber gratings are combined toward an increase of the sensitivity to strain of this type of devices: the dispersion turning point (DTP) and the cladding diameter ...
    • Sensitivity enhancement experimental demonstration using a low cutoff wavelength SMS modified structure coated with a pH sensitive film 

      Rodríguez-Rodríguez, W.E.; Del Villar, Ignacio; Zamarreño, Carlos R.; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Rodríguez-Rodríguez, A.J.; Domínguez-Cruz, R.F. (Elsevier, 2018)   Artículo / Artikulua
      The multimode interference (MMI) effect in a single mode-multimode-single mode (SMS) can be used fordevelopment of wavelength shift detection based sensors. In this work, the focus is centered on obtainingwavelength shifts ...
    • Nanofabrication of phase-shifted Bragg gratings on the end facet of multimode fiber towards development of optical filters and sensors 

      Gallego, E.E.; Ascorbe Muruzabal, Joaquín Upna; Del Villar, Ignacio; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (Elsevier, 2018)   Artículo / Artikulua
      This work describes the process of nanofabrication of phase-shifted Bragg gratings on the end facet of a multimode optical fiber with a pulsed DC sputtering system based on a single target. Several structures have been ...
    • Label-free wavelength and phase detection based SMS fiber immunosensors optimized with cladding etching 

      Cardona-Maya, Yamile; Socorro Leránoz, Abián Bentor Upna; Del Villar, Ignacio; Cruz, José Luis; Corres Sanz, Jesús María Upna; Botero Cadavid, J. F. (Elsevier, 2018)   Artículo / Artikulua
      The performance of E-SMS (Etched Singlemode-Multimode-Singlemode) optical fiber structures as immunosensors has been assessed by the implementation of antibody/antigen immunoassays. Through this procedure it has been ...
    • Long period fiber grating for biosensing: an improved design methodology to enhance add-layer sensitivity 

      Bandyopadhyay, Sankhyabrata; Del Villar, Ignacio; Basumallick, Nandini; Biswas, Palas; Dey, Tanoy Kumar; Bandyopadhyay, Somnath (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      We present our theoretical study on the design of LPFG sensor where its add-layer sensitivity is enhanced. addlayer sensitivity quantifies the sensitivity of the sensor to the changes taking place within few tens of ...
    • Characterization of microring filters for differential group delay applications 

      Doménech, D.; Chamorro Posada, P.; Fraile Pelaez, F.J.; Erro Betrán, María José Upna; Tainta Ausejo, Santiago Upna; Muriel, M.A.; Baños, R.; Bolten, J.; Kleinjans, H. (IEEEOptical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      The longitudinal offset technique permits to improve the accuracy of the coupling coefficients of integrated directional couplers and provides designs that can be easily implemented with current fabrication tolerances. ...
    • Metasurface-based ultrathin carpet cloaks for millimeter waves 

      Orazbayev, Bakhtiyar Upna; Mohammadi Estakhri, Nasim; Alù, Andrea; Beruete Díaz, Miguel Upna (2017)   Artículo / Artikulua  OpenAccess
      A metasurface carpet cloak for millimetre-wave range with polarization independent performance is experimentally demonstrated. It is shown that the cloak is able to mimic the ground plane by fully restoring the amplitude ...
    • Cyclic coding for Brillouin optical time-domain analyzers using probe dithering 

      Iribas Pardo, Haritz Upna; Loayssa Lara, Alayn Upna; Sauser, Florian; Llera, Miguel; Le Floch, Sébastien (Optical Society of America, 2017)   Artículo / Artikulua
      We study the performance limits of mono-color cyclic coding applied to Brillouin optical time-domain analysis (BOTDA) sensors that use probe wave dithering. BOTDA analyzers with dithering of the probe use a dual-probe-sideband ...
    • 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 ...
    • High aperture efficiency wide corrugations bull’s-eye antenna working at 60 GHz 

      Beaskoetxea Gartzia, Unai Upna; Beruete Díaz, Miguel Upna (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      A full metallic Bull’s-Eye (BE) antenna operating at 60 GHz is numerically and experimentally analyzed. The antenna presents wide grooves, rather than narrow ones, which support higher order resonances that lead to a large ...
    • Response of complementary split ring resonators in composite stratified substrate integrated waveguide 

      Pérez Escudero, José Manuel Upna; Jarauta Ayensa, Eduardo Upna; Falcone Lanas, Francisco Javier Upna; Beruete Díaz, Miguel Upna (American Institute of Physics, 2017)   Artículo / Artikulua
      In this work, the behavior of a Complementary Split Ring Resonator (CSRR) operating within the quasi-static resonance regime and embedded in a composite stratified Substrate Integrated Waveguide (SIW) with two different ...
    • Nonbianisotropic complementary split ring resonators as angular selective metasurfaces 

      Rodríguez Ulibarri, Pablo Upna; Beruete Díaz, Miguel Upna (Optical Society of America, 2017)   Artículo / Artikulua
      In this work, a metasurface with unconventional angular performance and composed by a nonbianisotropic complementary split ring resonator (NB-CSRR) is analyzed numerically and experimentally. A numerical study comparing ...
    • 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 Upna; 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 ...
    • Experimental realization of an epsilon-near-zero graded-index metalens at terahertz frequencies 

      Pacheco Peña, Víctor Upna; Engheta, Nader; Kuznetsov, Sergei A.; Gentselev, Alexandr; Beruete Díaz, Miguel Upna (American Physical Society, 2017)   Artículo / Artikulua  OpenAccess
      The terahertz band has been historically hindered by the lack of efficient generators and detectors, but a series of recent breakthroughs have helped to effectively close the “terahertz gap.” A rapid development of terahertz ...
    • 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
      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 ...
    • Optical fibre sensors using graphene-based materials: a review 

      Hernáez Sáenz de Zaitigui, Miguel Upna; Ruiz Zamarreño, Carlos Upna; Melendi Espina, Sonia; Bird, Liam; Mayes, Andrew; Arregui San Martín, Francisco Javier Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      Graphene and its derivatives have become the most explored materials since Novoselov and Geim (Nobel Prize winners for Physics in 2010) achieved its isolation in 2004. The exceptional properties of graphene have attracted ...
    • Recent developments in fiber optics humidity sensors 

      Ascorbe Muruzabal, Joaquín Upna; Corres Sanz , Jesús María Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      A wide range of applications such as health, human comfort, agriculture, food processing and storage, and electronic manufacturing, among others, require fast and accurate measurement of humidity. Sensors based on optical ...
    • Humidity sensor based on Bragg gratings developed on the end facet of an optical fiber by sputtering of one single material 

      Ascorbe Muruzabal, Joaquín Upna; Corres Sanz , Jesús María Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      The refractive index of sputtered indium oxide nanocoatings has been altered just by changing the sputtering parameters, such as pressure. These induced changes have been exploited for the generation of a grating on the ...
    • Is there a frontier in sensitivity with lossy mode resonance (LMR) based refractometers? 

      Ozcariz Celaya, Aritz; Ruiz Zamarreño, Carlos Upna; Zubiate Orzanco, Pablo; Arregui San Martín, Francisco Javier Upna (Nature Publishing Group, 2017)   Artículo / Artikulua  OpenAccess
      A tin dioxide thin layer has been studied in order to improve the sensitivity of lossy mode resonances (LMR) based sensors. The effects of the thin film thickness and the polarization of light in a SnO2 coated D-shaped ...