Now showing items 1-7 of 7

    • Amorphous glass-coated ferromagnetic wires in microwave engineering 

      Liberal Olleta, Íñigo Upna (2013)   Tesis doctoral / Doktoretza tesia  OpenAccess
      En esta tesis se ha estudiado el uso de hilos ferromagnéticos recubiertos de vidrio en ingeniería de microondas. Para este fin, se han formulado modelos analíticos y equivalentes circuitales de la interacción entre un ...
    • Bulk optical of potato flesh in the 500 – 1900 nm range 

      López-Maestresalas, Ainara Upna; Aernouts, Ben; Beers, Robbe van; Arazuri Garín, Silvia Upna; Jarén Ceballos, Carmen Upna; Baerdemaeker, Josse de; Saeys, Wouter (Springer US, 2015)   Artículo / Artikulua  OpenAccess
      In this study, the optical properties of potato flesh tissue were estimated using double-integrating sphere (DIS) measurements combined with an inverse adding-doubling (IAD) light propagation model. Total reflectance, ...
    • Error in radar-derived soil moisture due to roughness parameterization: an analysis based on synthetical surface profiles 

      Lievens, Hans; Vernieuwe, Hilde; Álvarez-Mozos, Jesús Upna; Baets, Bernard de; Verhoest, Niko E. C. (MDPI, 2009)   Artículo / Artikulua  OpenAccess
      In the past decades, many studies on soil moisture retrieval from SAR demonstrated a poor correlation between the top layer soil moisture content and observed backscatter coefficients, which mainly has been attributed ...
    • Influence of surface roughness measurement scale on radar backscattering in different agricultural soils 

      Martínez de Aguirre Escobar, Alejandro Upna; Álvarez-Mozos, Jesús Upna; Lievens, Hans; Verhoest, Niko E. C. (IEEE, 2017)   Artículo / Artikulua
      Soil surface roughness strongly affects the scattering of microwaves on the soil surface and determines the backscattering coefficient (σ 0 ) observed by radar sensors. Previous studies have shown important scale issues ...
    • Influence of surface roughness spatial variability and temporal dynamics on the retrieval of soil moisture from SAR observations 

      Álvarez-Mozos, Jesús Upna; Verhoest, Niko E. C.; Larrañaga, Arantzazu Upna; Casalí Sarasíbar, Javier Upna; González Audicana, María Upna (MDPI, 2009)   Artículo / Artikulua  OpenAccess
      Radar-based surface soil moisture retrieval has been subject of intense research during the last decades. However, several difficulties hamper the operational estimation of soil moisture based on currently available ...
    • A multipolar analysis of near-field absorption and scattering processes 

      Liberal Olleta, Íñigo Upna; Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna; Ziolkowski, Richard W. (IEEE, 2013)   Artículo / Artikulua  OpenAccess
      A multipolar formulation is adopted to investigate the absorption and scattering processes involved in near-field interactions. This approach allows one to determine the upper bounds for the absorbed and radiated powers ...
    • Remote (250 km) fiber Bragg grating multiplexing system 

      Fernández Vallejo, Montserrat Upna; Rota Rodrigo, Sergio Upna; López-Amo Sáinz, Manuel Upna (MDPI, 2011)   Artículo / Artikulua  OpenAccess
      We propose and demonstrate two ultra-long range fiber Bragg grating (FBG) sensor interrogation systems. In the first approach four FBGs are located 200 km from the monitoring station and a signal to noise ratio of 20 dB ...