Artículos de revista DIEE - IEES Aldizkari artikuluak

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Open Access
Fiber optic and KNX sensors network for remote monitoring a new building cladding system
(Elsevier, 2013) Unzu Ripoll, Ruth; Nazábal Urriza, Juan Antonio; Vargas Silva, Gustavo Adolfo; Hernández, Rufino; Fernández Valdivielso, Carlos; Urriza Ezcurra, Nuria; Galarza Galarza, Marko; López-Amo Sáinz, Manuel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC
Open Access
Single-mode-multimode-single-mode fiber (SMS): exploring environmental sensing capabilities
(IEEE, 2024-08-16) Díaz Lucas, Silvia; Armendáriz Ballesteros, Mikel; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
In this paper, we study the environmental sensing capabilities of a Single-Mode-Multimode-Single-Mode (SMS) fiber in a simple low-cost configuration. SMS fibers exhibit sensitivity to temperature, humidity, refractive index and strain, making them suitable for numerous applications in telecommunications, environmental monitoring, and more. Experimental results demonstrate that the sensor achieves a maximum temperature sensitivity of 4.53 nm/°C. Additionally, SMS fibers can also work as humidity sensors by absorbing or releasing moisture, leading to variations in the refractive index. Monitoring these changes allows for precise humidity measurements, with a sensitivity of 0.1548 nm/%RH. Moreover, SMS fibers show a refractive index sensitivity of 39.65 nm/RIU and strain sensitivities as high as 1.062 nm/¿¿, indicating good performance.
Open Access
Unibertsitateko irakaslegaiek Lehen Hezkuntzako ikasleentzat Txikipedian sortutako matematikako edukien egokitasuna neurtzen
(Udako Euskal Unibertsitatea, UEU, 2022-12-02) Iribas Pardo, Haritz; Errazkin Vicente, Aitor; Torrealday Gallarreta, Amaia; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Artikulu honek baliozkotze-prozesu bat biltzen du, zeinak egiaztatu nahi izan duen Lehen Hezkuntzako ikasleek matematikako edukiak ulertzeko Txikipedia lagungarri izan duten ala ez, bai testuari zein testuaren osagarri diren ikus-entzunezkoei erreparatuta. Txikipediako matematikako edukiak Mondragon Unibertsitateko Lehen Hezkuntza Graduan irakasle izateko ikasketak egiten ari diren ikasleek sortu dituzte eta Euskal Herriko sei ikastetxetan baliozkotu dira. Emaitzek erakutsi dute Txikipediako sarrerak irakurtzea lagungarria dela ikasleentzat, nahiz eta ikusentzunezkoen ekarpenarekin lotutako emaitzek galdera berriak sorrarazi dituzten. Hala ere, esan dezakegu humanitate digitalek lagun dezaketela matematikaren irakaskuntza hobetzen, bai irakaslegaien formakuntzan zein ikasleen edukien ulermenean ere.
Open Access
Femtomolar detection by nanocoated fiber label-free biosensors
(American Chemical Society, 2018) Chiavaioli, Francesco; Zubiate Orzanco, Pablo; Del Villar, Ignacio; Ruiz Zamarreño, Carlos; Giannetti, Ambra; Tombelli, Sara; Trono, Cosimo; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Baldini, Francesco; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
The advent of optical fibre-based biosensors combined with that of nanotechnologies has provided an oppor-tunity for developing in situ, portable, lightweight, versatile and high-performance optical sensing platforms. We report on the generation of lossy mode resonances by the deposition of nm-thick metal oxide films on optical fibres, which makes it possible to measure precisely and accurately the changes in optical properties of the fibre-surrounding medium with very high sensitivity compared to other technology platforms, such as long period gratings or surface plasmon resonances, the gold standard in label-free and real-time biomolecular interaction analysis. This property, combined with the application of specialty structures such as D-shaped fibres, permits enhancing the light-matter interaction. SEM and TEM imaging together with X-EDS tool have been utilised to characterise the two films used, i.e. indium tin oxide and tin dioxide. More-over, the experimental transmission spectra obtained after the deposition of the nanocoatings have been numerically cor-roborated by means of wave propagation methods. With the use of a conventional wavelength interrogation system and ad-hoc developed microfluidics, the shift of the lossy mode resonance can be reliably recorded in response to very low analyte concentrations. Repeated experiments confirm a big leap in performance thanks to the capability to detect femtomolar concentrations in human serum, improving the detection limit by three orders of magnitude when compared with other fibre-based configurations. The biosensor has been regenerated several times by injecting sodium dodecyl sul-phate, which proves the capability of sensor to be reused.
Open Access
Experimental demonstration of lossy mode resonance generation for transverse-magnetic and transverse-electric polarizations
(Optica Publishing Group, 2013) Ruiz Zamarreño, Carlos; Zubiate Orzanco, Pablo; Sagüés García, Mikel; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This Letter, presents the fabrication of lossy mode resonance (LMR) devices based on titanium dioxide (TiO2)/ poly(sodium 4-styrenesulfonate) (PSS) coatings deposited on side-polished D-shaped optical fibers. TiO2 thin films have been obtained by means of the layer-by-layer (LbL) self-assembly technique. LbL enables us to produce smooth and homogeneous coatings on the polished side of the fiber. This permits us to couple light from the waveguide to the TiO2-coating/external medium region at specific wavelength ranges. The generation of LMRs depends on the coating thickness, so that thicker coatings can produce more resonances. LMRs are sensitive to the external medium refractive index, which allows its utilization as refractometers. The characteristic D-shaped architecture of the devices employed in this Letter enables us to distinguish TE and TM polarizations, which had not been possible before with regular optical fibers due to their cylindrical symmetry. The results presented here show for the first time the experimental demonstration of the generation of LMRs produced by both TM and TE polarizations. More specifically, for these TiO2/PSS thin films, the TM and TM modes of the LMRs show a wavelength shift of 226 nm for the first-order LMR and 56 nm for the second-order LMR.
Open Access
Using S-parameter measurements to determine the threshold voltage, gain factor, and mobility degradation factor for microwave bulk-MOSFETs
(Elsevier, 2011) Álvarez Botero, Germán Andrés; Torres-Torres, Reydezel; Murphy-Arteaga, Roberto S.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, we present an extraction and characterization methodology which allows for the determination, from S-parameter measurements, of the threshold voltage, the gain factor, and the mobility degradation factor, neither requiring data regressions involving multiple devices nor DC measurements. This methodology takes into account the substrate effects occurring in MOSFETs built in bulk technology so that physically meaningful parameters can be obtained. Furthermore, an analysis of the substrate impedance is presented, showing that this parasitic component not only degrades the performance of a microwave MOSFET, but may also lead to determining unrealistic values for the model parameters when not considered during a high-frequency characterization process. Measurements were made on transistors of different lengths, the shortest being 80 nm, in the 10 MHz to 40 GHz frequency range.
Open Access
Modeling and parameter extraction of test fixtures for MOSFET on-wafer measurements up to 60 GHz
(Wiley, 2013) Álvarez Botero, Germán Andrés; Torres-Torres, Reydezel; Murphy-Arteaga, Roberto S.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We present a circuit model and parameter determination methodology for test fixtures used for on-wafer S-parameter measurements on CMOS devices. The model incorporates the frequency dependence of the series resistances and inductances due to the skin effect occurring in the metal pads. Physically based representations for this effect allow for excellent theory-experiment correlations for different dummy structures, as well as when de-embedding transistor measurements up to 60 GHz.
Open Access
Characterization of RF-MOSFETs in common-source configuration at different source-to-bulk voltages from S-parameters
(IEEE, 2013) Zárate-Rincón, Fabián; Álvarez Botero, Germán Andrés; Torres-Torres, Reydezel; Murphy-Arteaga, Roberto S.; Decoutere, Stefaan; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Using a new test fixture that allows us to bias the bulk terminal through an additional compensated DC probe, a two-port S-measurement-based methodology to characterize RF-MOSFETs in common-source configuration is herein presented. In addition to obtaining S-parameters at different bulk-to-source voltages using a single two-port configured test-fixture, the proposal allows the analysis of the electrical parameters of a MOSFET that are influenced by the substrate effect when the frequency rises. Physically expected results are obtained for device's model parameters, allowing to accurately reproduce S-parameters up to 20 GHz. Furthermore, extracted parameters, such as threshold voltage, are in agreement with those obtained using well-established DC methods. This method allows one to characterize a four-terminal MOSFET from two-port small-signal measurements.
Open Access
Consistent modeling and power gain analysis of microwave SiGe HBTs in CE and CB configurations
(IEEE, 2015) Álvarez Botero, Germán Andrés; Torres-Torres, Reydezel; Murphy-Arteaga, Roberto S.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This paper presents a methodology to model SiGe HBTs biased in common-emitter and in common-base configurations including the bias-dependent substrate parasitics, which allows determining the more suitable configuration to achieve maximum power gain at different frequency ranges. Model-experiment correlations up to 100 GHz for different bias conditions verify the validity of the proposed circuit representations using the same values for the parameters in both configurations.
Open Access
Characterization and modeling of the capacitive HBC Channel
(IEEE, 2015) Pereira, Maicon D.; Álvarez Botero, Germán Andrés; Sousa, Fernando Rangel de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The increasing interest in wireless body area networks has created the need for alternative communication schemes. One example of such schemes is the use of the human body as a communication medium. This technology is called human body communication (HBC), and it offers advantages over the most common radiation-based methods, which makes it an interesting alternative to implement body area networks. The aim of this paper is to identify the influence of a fixture on the HBC channel characterization, and an extended model that includes the test fixtures to explain the measured channel response is proposed. The model was tested against the channel measurement results, and a good experiment-model correlation was obtained. The results show that the test fixture has a nonnegligible influence and that an extended model, based on the physical meaning of the phenomena involved, helps to explain the channel frequency profile results and behavior.
Open Access
Theoretical modeling and experimental verification of the scattering from a ferromagnetic microwire
(IEEE, 2011) Liberal Olleta, Íñigo; Ederra Urzainqui, Íñigo; Gómez Polo, Cristina; Labrador Otamendi, Alberto; Pérez de Landazábal Berganzo, José Ignacio; Gonzalo García, Ramón; Física; Fisika; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This contribution presents a theoretical modelling of the scattering of ferromagnetic microwires in free-space and inside a rectangular waveguide, providing both an analytical solution and a physical interpretation of the problem. Special attention is devoted to the impact of the microwire radius and its magnetic properties. Theoretical results have been experimentally verified measuring the reflection, absorption and transmission coefficients of a ferromagnetic microwire inside a rectangular waveguide.
Open Access
Manipulating thermal emission with spatially static fluctuating fields in arbitrarily shaped epsilon-near-zero bodies
(National Academy of Sciences, 2018) Liberal Olleta, Íñigo; Engheta, Nader; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The control and manipulation of thermal fields is a key scientific andtechnological challenge, usually addressed with nanophotonic struc-tures with a carefully designed geometry. Here, we theoreticallyinvestigate a different strategybased on epsilon-near-zero (ENZ)media. We demonstrate that thermal emission from ENZ bodies ischaracterized by the excitation of spatially static fluctuating fields,which can be resonantly enhanced with the addition of dielectricparticles. The“spatially static”character of these temporally dynamicfields leads to enhanced spatial coherence on the surface of the body,resulting in directive thermal emission. By contrast with other ap-proaches, this property is intrinsic to ENZ media and it is not tied toits geometry. This point is illustrated with effects such as geometry-invariant resonant emission, beamforming by boundary deforma-tion, and independence with respect to the position of internalparticles. We numerically investigate a practical implementationbased on a silicon carbide body containing a germanium rod.
Open Access
Optimized wireless channel characterization in large complex environments by hybrid ray launching-collaborative filtering approach
(IEEE, 2017) Casino, Fran; Azpilicueta Fernández de las Heras, Leyre; López Iturri, Peio; Aguirre Gallego, Erik; Falcone Lanas, Francisco; Solanas, Agustí; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Simulation techniques based on deterministic methods such as Ray Tracing and Ray Launching, are widely used to perform radioplanning tasks. However, the quality of the simulations depends on the number of rays and the angular resolution. The computational cost of these simulations in High Definition prevents their use in complex environments and their Low Definition counterparts are used instead. In this article we propose a technique based on collaborative filtering to lessen the poor quality problems of Low Definition simulations. We show that our approach obtains results very similar to those of High Definition in much less time. Also, we compare our approach with other well-known techniques and we show that it performs better in terms of accuracy and precision. The use of combined deterministic/collaborative filtering techniques allows the estimation of radioplanning tasks in large, complex scenarios with a potentially large amount of transceivers.
Open Access
Photonic crystal fiber interferometer coated with a PAH/PAA nanolayer as humidity sensor
(Elsevier, 2017) López Torres, Diego; Elosúa Aguado, César; Villatoro, Joel; Zubia, Joseba; Rothhardt, Manfred; Schuster, K.; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC
In this paper, an optical fiber interferometric humidity sensor is presented. The device consists of 1 cmlong segment of photonic crystal fiber (PCF) spliced to standard single mode fibers (SMFs), forming an interferometer: the two collapsed interfaces between PCF and SMF segments produce the excitation and recombination of core and cladding modes. The latter interact with a poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) polymeric nanocoating deposited on the PCF by the well-established layer-by-layer nano assembly (LbL) technique. Humidity modifies the index of the polymeric nanolayer which in turns alters the cladding modes along the PCF segment and causes a detectable shift to the interference pattern. A study of different nanocoting thicknesses is presented in order to obtain the best possible sensibility for the sensor. Furthermore, the interrogation of the humidity sensor is presented not only by the conventional study of the spectrum shift amplitude, but also making use of the Fast Fourier Transform (FFT), which yields a linearization of the device response. The sensor here presented is reproducible, can resolve 0.074% of relative humidity (RH) and operates in the 20–95% RH range. Moreover, it exhibits response time of 0.3 s, a negligible cross sensitivity to temperature as well as long term stability.
Open Access
From superhydrophilic to superhydrophobic surfaces by means of polymeric Layer-by-Layer films
(Elsevier, 2015) López Torres, Diego; Elosúa Aguado, César; Hernáez Sáenz de Zaitigui, Miguel; Goicoechea Fernández, Javier; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Open Access
Enhancing sensitivity of photonic crystal fiber interferometric humidity sensor by the thickness of SnO2 thin films
(Elsevier, 2017) López Torres, Diego; Elosúa Aguado, César; Villatoro, Joel; Zubia, Joseba; Rothhardt, Manfred; Schuster, K.; Arregui San Martín, Francisco Javier; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Open Access
Experimental study and sensing applications of polarization-dependent lossy mode resonances generated by D-shape coated optical fibers
(IEEE, 2015) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The fabrication and characterization of an optical fiber refractometer based on Lossy Mode Resonances (LMR) is presented. TiO2/ poly (sodium 4-styrenesulfonate) (PSS) coatings deposited on side-polished D-shaped optical fibers are used as LMR supporting coatings. LMRs are sensitive to the external medium refractive index and D-shaped optical fibers enable the observation of TE and TM LMR polarizations. These refractometers based on TE and TM LMR showed an average sensitivity of 2737 nm/RIU and 2893 nm/RIU respectively for a surrounding medium refractive index (SMRI) range from 1.35 to 1.41. This work also explores the utilization of previously described refractometers in the context of two common industrial applications such as the determination of the sugar content or °Brix in beverages and the salt concentration in sea water.
Open Access
High sensitive and selective C-reactive protein detection by means of lossy mode resonance based optical fiber devices
(Elsevier, 2017) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Sánchez Zábal, Pedro; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This work presents the development of high sensitive, selective, fast and reusable C-reactive protein (CRP) aptasensors. This novel approach takes advantage of the utilization of high sensitive refractometers based on Lossy Mode Resonances generated by thin indium tin oxide (ITO) films fabricated onto the planar region of D-shaped optical fibers. CRP selectivity is obtained by means of the adhesion of a CRP specific aptamer chain onto the ITO film using the Layer-by-Layer (LbL) nano-assembly fabrication process. The sensing mechanism relies on resonance wavelength shifts originated by refractive index variations of the aptamer chain in presence of the target molecule. Fabricated devices show high selectivity to CRP when compared with other target molecules, such as urea or creatinine, while maintaining a low detection limit (0.0625 mg/L) and fast response time (61 s). Additionally, these sensors show a repetitive response for several days and are reusable after a cleaning process in ultrapure water.
Open Access
Tunable optical fiber pH sensors based on TE and TM Lossy Mode Resonances (LMRs)
(Elsevier, 2016) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, a high sensitivity optical fiber pH sensor based on lossy mode resonance (LMR) generated with transversal electric (TE) and transversal magnetic (TM) polarized light is presented. Poly(allylamine hydrochloride) (PAH)/poly(acrylic acid) (PAA) polymeric thin-films fabricated onto side-polished Dshaped optical fibers are used as pH-sensitive as well as LMR supporting coatings. The adequate selection of the pH-sensitive coating fabrication parameters enables to obtain devices working at different pH regions. Two devices have been obtained in order to measure pH from 4.0 to 5.0 and from 7.0 to 8.0 respectively. Obtained optical fiber pH sensors based on TE and TM LMRs showed a maximum sensitivity of 69 nm/pH, which means a resolution of ∼0.0008 pH units by using a conventional communications Optical Spectrum Analyzer (OSA) with 0.06 nm resolution.
Open Access
Single-mode-multimode-single-mode and lossy mode resonance-based devices: a comparative study for sensing applications
(Springer-Verlag, 2015) Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Corres Sanz, Jesús María; Del Villar, Ignacio; Hernáez Sáenz de Zaitigui, Miguel; Socorro Leránoz, Abián Bentor; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC