Person:
Rodríguez Ulibarri, Pablo

person.page.identifierURI

https://academica-e.unavarra.es/handle/2454/49887

Last Name

Rodríguez Ulibarri

First Name

Pablo

person.page.departamento

Ingeniería Eléctrica y Electrónica

ORCID

0000-0001-5705-5457

person.page.upna

810935

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Now showing 1 - 10 of 23

Open Access
Low profile THz periodic leaky-wave antenna
(IEEE, 2014) Beaskoetxea Gartzia, Unai; Beruete Díaz, Miguel; Rodríguez Ulibarri, Pablo; Etayo Salinas, David; Sorolla Ayza, Mario; Navarro Cía, Miguel; Zehar, Mokhtar; Blary, Karine; Chahadih, Abdallah; Han, Xiang-Lei; Akalin, Tahsin; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, a 0.566THz flat leaky-wave antenna, consisting of a central λ0/2 slot surrounded by straight parallel wedge corrugations, is numerically and experimentally analyzed. Simulations show a moderately high gain and no significant differences when compared with a typical square corrugation profile. Numerical comparison is also made for the designed and manufactured antennas. High transmission enhancement in the corrugated case is obtained, compared to that given by a single central slot with no grooves. This kind of antennas finds several applications in different frequency ranges, including the nowadays high-interest range of the THz.
Open Access
Blind spot mitigation in phased array antenna using metamaterials
(IEEE, 2014) Crépin, Thomas; Martel, Cédric; Gabard, Benjamin; Boust, Fabrice; Martinaud, Jean-Paul; Dousset, Thierry; Rodríguez Ulibarri, Pablo; Beruete Díaz, Miguel; Loecker, Claudius; Bertuch, Thomas; Marcotegui Iturmendi, José Antonio; Maci, Stefano; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, a metaradome based on a fakir’s bed of nails is designed and tested in order to suppress the blind directions of a 100-element antenna array. The antenna is a microstrip array designed to operate in X-band. The fakir’s bed metamaterial-like was first approximated using analytical formulas before a full-wave numerical optimization. Experimental results are exposed and confronted to numerical results. They show a significant reduction of the blind spot subsequent to the metaradome addition.
Open Access
Labyrinth metasurface for biosensing applications: numerical study on the new paradigm of metageometries
(MDPI, 2019) Jáuregui López, Irati; Rodríguez Ulibarri, Pablo; Kuznetsov, Sergei A.; Quemada Mayoral, Carlos; Beruete Díaz, Miguel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The use of metasurfaces operating in the terahertz regime as biosensor devices has attracted increased interest in recent years due to their enhanced sensitivity and more accurate detection capability. Typical designs are based on the replica of relatively simple unit cells, usually called metaatoms. In a previous paper, we proposed a new paradigm for ultrasensitive thin-film sensors based on complex unit cells, called generically metageometries or labyrinth metasurfaces. Here, we extend this concept towards biosensing, evaluating the performance of the labyrinth as a fungi detector. The sensing capabilities are numerically evaluated and a comparison with previous works in this field is performed, showing that metageometries improve the performance compared to metaatoms both in sensitivity and figure of merit, by a factor of more than four. In particular, we find that it is able to detect five fungi elements scattered on the unit cell, equivalent to a concentration of only 0.004/µm2.
Open Access
Nonbianisotropic complementary split ring resonators as angular selective metasurfaces
(Optical Society of America, 2017) Rodríguez Ulibarri, Pablo; Beruete Díaz, Miguel; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
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 the performance with the original complementary split ring resonator is conducted, showing very interesting transmission properties, such as complete filtering under normal incidence and high transmission peaks at oblique incidence for the NB-CSRR metasurface. A bilayered NB-CSRR prototype working at millimeter waves with a total thickness of 100 μm (0.1 times the operation wavelength) is fabricated and tested with a good agreement between simulation results and experiments. Very exciting applications based on the presented structure, such as advanced angular selectivity devices with great rejection levels at normal incidence and angular sensing devices, can be envisaged.
Open Access
Mid-infrared spectroscopy (MIR) for simultaneous determination of fat and protein content in meat of several animal species
(Springer, 2017) Lozano Saiz, María; Rodríguez Ulibarri, Pablo; Echeverría Morrás, Jesús; Beruete Díaz, Miguel; Sorolla Ayza, Mario; Beriain Apesteguía, María José; Institute of Smart Cities - ISC; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Institute for Advanced Materials and Mathematics - INAMAT2
The aim of this research was to study the application of MIR spectroscopy as an alternative to conventional methods to determine fat and protein content. Samples of the main species used to produce meat products were analyzed, showing all of them absorption bands at similar wavenumbers though with different intensity. Correlation analysis of absorption intensities showed that bands around 2925, 2854, and 1746 cm−1 are associated with fat content, whereas bands around 3288, 1657, and 1542 cm−1 are associated with proteins. During the validation process, prediction models of fat and protein content were successfully obtained withR2 0.9173 and 0.7534, respectively. Finally, a good result (R2 =0.8829) was obtained on the estimation of the lipid content when the information at only one wavenumber was used.
Open Access
One-way quasiplanar terahertz absorbers using nonstructured polar dielectric layers
(American Physical Society, 2017) Rodríguez Ulibarri, Pablo; Serebryannikov, Andriy E.; Beruete Díaz, Miguel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A concept of quasiplanar one-way transparent terahertz absorbers made of linear isotropic materials is presented. The resulting structure consists of a homogeneous absorbing layer of polar dielectric, GaAs, a dispersion-free substrate, and an ultrathin frequency-selective reflector. It is demonstrated that perfect absorption can be obtained for forward illumination, along with total reflection at backward illumination and transparency windows in the adjacent bands. The design is particularized for the polaritonic gap range where permittivity of GaAs varies in a wide range and includes epsilon-near-zero and transparency regimes. The underlying physics can be explained with the aid of a unified equivalent-circuit (EC) analytical model. Perfect matching of input impedance in forward operation and, simultaneously, strong mismatch in the backward case are the universal criteria of one-way absorption. It is shown that perfect one-way absorption can be achieved at rather arbitrary permittivity values, provided these criteria are fulfilled. The EC results are in good agreement with full-wave simulations in a wide range of material and geometrical parameters. The resulting one-way absorbers are very compact and geometrically simple, and enable transparency in the neighboring frequency ranges and, hence, multifunctionality that utilizes both absorption- and transmission-related regimes.
Open Access
Wide angle terahertz sensing with a cross-dipole frequency selective surface
(AIP Publishing, 2016) Rodríguez Ulibarri, Pablo; Kuznetsov, Sergei A.; Beruete Díaz, Miguel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this work, a terahertz sensor based on a cross dipole frequency selective surface is analyzed and experimentally tested. The sensing structure is optimized for operation at the fundamental band- stop resonance near 0.7THz and characterized under normal and oblique incidence. The sensing performance as a function of the incidence angle and the wave polarization is evaluated with good agreement between simulations and measurements. It is shown that a figure of merit for the pro- posed sensor can be enhanced from 0.2 up to 0.6 due to switching from normal to oblique excita- tion, which yields the maximum performance for TM polarization at the incidence angle of 70º. The presented results demonstrate a wide angle operation regime in THz sensing that opens up an alternative approach in improving capabilities of sensing devices.
Open Access
On the performance of an ENZ-based sensor using transmission line theory and effective medium approach
(IOP Publishing, 2019) Pacheco-Peña, Víctor; Beruete Díaz, Miguel; Rodríguez Ulibarri, Pablo; Engheta, Nader; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería Eléctrica, Electrónica y de Comunicación
In this paper we perform an in-depth theoretical studyofa sensing platform based on epsilon-near- zero (ENZ) metamaterials. The structure proposed for sensing is a narrow metallic waveguide channel. An equivalent circuit model is rigorouslydeduced using transmission line theory, considering several configurations for a dielectric body (analyte sample) inserted within the narrow channel, showing good agreement with results obtained from numerical simulations. The transmission line model is able to reproduce even the most peculiar details ofthe sensing platform response. Its performance is then evaluated byvarying systematically the size, position and permittivity ofthe analyte, and height ofthe ENZ channel. It is shown that the sensor is capable ofdetecting changes in the permittivity/ refractive index or position even with deeplysubwavelength analyte sizes (∼0.05λ0), giving a sensitivity up to 0.03m/RIU and a figure ofMerit∼25. The effective medium approach is evaluated by treating the inhomogeneous cross-section ofthe analyte as a transmission line filled with a homogeneous material.
Open Access
Labyrinth metasurface absorber for ultra-high-sensitivity terahertz thin film sensing
(Wiley, 2018) Jáuregui López, Irati; Rodríguez Ulibarri, Pablo; Urrutia Azcona, Aitor; Kuznetsov, Sergei A.; Beruete Díaz, Miguel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this work, a labyrinth metasurface sensor operating at the low‐frequency edge of the THz band is presented. Its intricate shape leads to a high electric field confinement on the surface of the structure, resulting in ultrasensitive performance, able to detect samples of the order of tens of nanometers at a wavelength of the order of millimeters (i.e., five orders of magnitude larger). The sensing capabilities of the labyrinth metasurface are evaluated numerically and experimentally by covering the metallic face with tin dioxide (SnO2) thin films with thicknesses ranging from 24 to 345 nm. A redshift of the resonant frequency is observed as the analyte thickness increases, until reaching a thickness of 20 μm, where the response saturates. A maximum sensitivity of more than 800 and a figure of merit near 4500 nm−1 are achieved, allowing discriminating differences in the SnO2 thickness of less than 25 nm, and improving previous works by a factor of 35. This result can open a new paradigm of ultrasensitive devices based on intricate metageometries overcoming the limitations of classical metasurface sensor designs based on periodic metaatoms.
Open Access
Analysis of antenna transient radiation
(2011) Rodríguez Ulibarri, Pablo; Gómez Laso, Miguel Ángel; Yarovoy, Alexander; Caratelli, Diego; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola Teknikoa; Delft University of Technology (Holanda); Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Recently a new formalism has been developed for modeling time domain radiation processes in complex antennas. Using this formalism the radiated electromagnetic field can be expressed in terms of non uniform spherical wave contributions relevant to the resonant phenomena occurring in the structure. The developed algorithm consists of a dedicated two-step vector fitting procedure. Firstly, the spherical harmonic expansion of the time-domain equivalent electric and magnetic currents is performed. Then, by using the Singularity-Expansion-Method (SEM), the time-variant spherical harmonic expansion coefficients are represented in terms of dumped exponential terms. In this way, by using the incomplete modified spherical Bessel functions, an analytical description of the transient wave radiation phenomena is achieved. In this study several canonical radiating structures such as dipole, bow-tie and loop antennas, have been analyzed using the afore-mentioned formalism in order to gain a physical insight into the natural resonant processes occurring in the antenna and find a relation with the relevant geometrical characteristics.