Open Access
Análisis del comportamiento de esquemas de modulación adaptativos en LTE
(2009) Torres Landívar, Víctor; Esparza Alfaro, Fermín; Falcone Lanas, Francisco; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, the behaviour of several modulation schemes used in 3GPP R8 or Long Term Evolution (LTE) Systems is analyzed. In order to increase the capacity of future mobile networks, high order modulation schemes like 64-QAM are envisaged, which have more stringent Signal-to-Noise restrictions. System simulation results for various modulation schemes regarding Error Vector Magnitude (EVM) values and constellation behaviour are obtained, showing dependence of quality degradation with bit rate, interference ratio and relative constellation position of the symbols. These results, related to constellation behaviour, can aid in the future design of high data rate mobility systems based on LTE.
Open Access
Mejora de antenas metalo-dieléctricas en la banda de frecuencias GSM-UMTS mediante elementos en transmisión extraordinaria
(2009) Illescas, Jesús; Estévez González, Aritz; Falcone Lanas, Francisco; Marcotegui Iturmendi, José Antonio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work a dual band GSM/UMTS antenna is proposed. The antenna is based on a stacked planar structure, where the combination of collimation by Enhanced Transmission and the use of parasitic director elements is used in order to achieve the desired specifications. Full wave simulation results, obtained using a self created algorithm based on the FDTD method, as well as measurement results from a fabricated prototype are presented, showing good agreement. The proposed antenna finds application in the deployment of micro and minicell sites in dual 2G/3G networks
Open Access
Comportamiento de propagacion electromagnetica en el apilamiento de agujeros sublambda y agujeros propagantes
(2009) Navarro Cía, Miguel; Beruete Díaz, Miguel; Falcone Lanas, Francisco; Campillo, Igor; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, we provide more insight on the physics underlying the transmission through subwavelength hole arrays metaprism by comparing it with propagating hole arrays prism. We show the critical role that the size of the holes plays in this electromagnetic propagation, changing the effective index of refraction from negative to positive values as the hole diameter increases. This causes negative refraction for the zero-th order emerging beam in the metaprism whereas positive refraction in the non-cut-off holes prism. Experimental results (co- and cross-polar measurements) performed at the V-band of the millimeter waves in the Fresnel zone are well supported by numerical analyses in terms of dispersion diagram, spatial electric field distribution and power flow within the prism along with in the output air zone. As expected, higher order diffracted outgoing beams are recorded for the classical prism but not for the metaprism.
Open Access
Split ring resonator-based left-handed coplanar waveguide
(AIP Publishing, 2003) Martín, F.; Bonache, J.; Falcone Lanas, Francisco; Sorolla Ayza, Mario; Marqués, R.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this letter, a planar left-handed propagating medium consisting of a coplanar waveguide (CPW) inductively coupled to split ring resonators (SRR) and periodically loaded with narrow metallic wires is proposed. The wires make the structure behave as a microwave plasma with a negative effective permittivity which covers a broad frequency range. The negative permeability required to achieve left-handed wave propagation is provided by the rings in the vicinity of their resonant frequency. The result is a structure which allows negative wave propagation in a narrow frequency band. The transmission coefficient measured in a fabricated prototype device exhibits very low insertion losses in the pass band and high-frequency selectivity. Since rings are much smaller than signal wavelength at resonance and can be easily tuned, SRR-CPW-based structures are of interest for the design of very compact microwave circuits based on left handedness.
Open Access
Comment on “A waveguide slit array antenna fabricated with subwavelength periodic grooves Appl. Phys. Lett. 91, 143512 (2007)”
(AIP Publishing, 2008) Beruete Díaz, Miguel; Falcone Lanas, Francisco; Sorolla Ayza, Mario; Campillo, Igor; Dolado, Jorge S.; Rodríguez Seco, J. E.; Perea, E.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We firmly think that it is proven that most of the ideas, results, and discussions presented in C. Huang, C. L. Du, and X. G. Luo, Appl. Phys. Lett. 91, 143512, 2007 were already present in our previous paper (M. Beruete, I. Campillo, J. S. Dolado, J. E. Rodríguez-Seco, E. Perea, F. Falcone, and M. Sorolla, IEEE Trans. Antennas Propag. 54, 340, 2006) and that the antenna design in Huang et al. cannot be considered original at all since it is identical to our design. The only innovative aspect in Huang et al. is the discussion about the multiple slit source.
Open Access
Implementacion de línea de ε negativa en tecnología stripline
(2009) Illescas, Jesús; Jarauta Ayensa, Eduardo; Estévez González, Aritz; Marcotegui Iturmendi, José Antonio; Falcone Lanas, Francisco; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, a negative-ε equivalent response medium is proponed in stripline technology. To achieve band rejection behaviour, Complementary Split Ring Resonators (CSRR) are placed in the central conductor strip of a conventional stripline planar transmission line. Due to strong normal electric field incidence, adequate excitation of the stripline is achieved, leading to band rejection in the quasi-static resonance frequency of the CSRR particles. Full wave simulation results from our own FDTD code and measurement results are presented, showing good agreement.
Open Access
Extraordinary transmission and left-handed propagation in miniaturized stacks of doubly periodic subwavelength hole arrays
(Optical Society of America, 2007) Beruete Díaz, Miguel; Sorolla Ayza, Mario; Navarro Cía, Miguel; Falcone Lanas, Francisco; Campillo, Igor; Lomakin, Vitaliy; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Metallic plates embedded between dielectric slabs and perforated by rectangular arrays of subwavelength holes with a dense periodicity in one of the directions support extraordinary transmission (ET) phenomena, viz. strong peaks in the transmittance frequency dependence. Stacks of such perforated plates support ET phenomena with propagation along the stack axis that is characterized by the left handed behavior. The incorporation of the dielectric materials and dense periodicity allows significantly reducing the illuminated area of the perforated plate required experimentally to observe the ET phenomena as compared to the areas required in the case of free standing rectangular hole arrays. This facilitates the experimental investigation of ET under excitation in the Fresnel zone of Gaussian beams.
Open Access
Ultra-wideband metamaterial filter based on electroinductive-wave coupling between microstrips
(EMW Publishing, 2009) Navarro Cía, Miguel; Carrasco, José Miguel; Beruete Díaz, Miguel; Falcone Lanas, Francisco; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, we analyse the frequency response of microstrip lines coupled by complementary split ring resonators (CSRRs) etched on the ground plane supporting electroinductive waves (EIWs). The single-particle configurations demonstrate the principle of operation whose bandwidths reach 67% of the central frequency. A double configuration is afterwards investigated as a further improvement of the filtering response, such as the level of the spurious lower frequency band. Finally, an ultimate prototype comprising different CSRRs along the access line, together with the aforementioned EIW-coupling is proposed for filtering undesired higher bands. Experimental results confirm numerical analysis.
Open Access
Broadband spoof plasmons and subwavelength electromagnetic energy confinement on ultrathin metafilms
(Optical Society of America, 2009) Navarro Cía, Miguel; Beruete Díaz, Miguel; Agrafiotis, Spyros; Falcone Lanas, Francisco; Sorolla Ayza, Mario; Maier, Stefan A.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A complementary split ring resonator (CSRR)-based metallic layer is proposed as a route to mimic surface plasmon polaritons. A numerical analysis of the textured surface is carried out and compared to previous prominent topologies such as metal mesh, slit array, hole array, and Sievenpiper mushroom surfaces, which are studied as well from a transmission line perspective. These well-documented geometries suffer from a narrowband response, alongside, in most cases, metal thickness constraint (usually of the order of λ/4) and non-subwavelength modal size as a result of the large dimensions of the unit cell (one dimensions is at least of the order of λ/2). All of these limitations are overcome by the proposed CSRR-based surface. Besides, a planar waveguide is proposed as a proof of the potential of this CSRR-based metallic layer for spoof surface plasmon polariton guiding. Fundamental aspects aside, the structure under study is easy to manufacture by simple PCB techniques and it is expected to provide good performance within the frequency band from GHz to THz.
Open Access
Electroinductive waves in chain of complementary metamaterial elements
(AIP Publishing, 2006) Beruete Díaz, Miguel; Falcone Lanas, Francisco; Freire, M. J.; Marqués, R.; Baena, J.D.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Electronductive waves supported by chains of resonators drilled on a metallic plate are presented. Propagation of energy comes as a consequence of the electric coupling between these resonators. Therefore, these waves are termed as electroinductive waves. They can be interpreted as the dual counterpart of the so-called magnetoinductive waves, which are due to the mutual inductances along chains of resonators. In order to show their existence, some electromagnetic simulations and experiments have been carried out, using as resonators the complementary particle of the split ring resonator. The reported result opens the way to a high variety of applications in one- and two-dimensional devices, such as transducers, delay lines, bends, power dividers, couplers, antennas, lenses, etc.