Open Access
Resultados experimentales de la mejora de potencia radiada por un dipolo mediante un superstrato left-handed
(2006) Sáenz Sáinz, Elena; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Maagt, Peter de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper a comparison between the measured radiation performances of a single dipole and a dipole with a left handed superstrate based on a finite periodic repetition of a unit cell is presented. First of all the return losses and resonant frequency of the dipole has been measured for different sizes of the superstrate, having a good impedance matching and a decrease in the resonant frequency as the number of cells increase. By using an anechoic chamber and a receiver horn antenna, the power transmitted at boresight has been measured for different frequencies, observing a filtering behaviour due to the resonant characteristic of the superstrate and an improvement of the power transmitted at the resonant frequency of around 3.5 dB. Comparing the H and E plane radiation patterns of a dipole and the dipole with superstrate, more symmetrical and directive radiation patterns can be observed. Finally, a comparison between the simulated and measured aperture efficiency is presented with a good agreement between them.
Open Access
Research on metamaterials for antenna applications
(2005) Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Iriarte Galarregui, Juan Carlos; Martínez Pascual, Beatriz; Sáenz Sáinz, Elena; Cantora Álvarez, Pablo; Maagt, Peter de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
During the last 20 years a lot of attention has been paid to apply Electromagnetic Band Gap (EBG) technology in different frequency ranges, from microwaves to optics. EBG technology is based on the use of periodic structures to prevent the electromagnetic propagation in certain frequency ranges, known as the bandgap [1]. In the last years the new and revolutionary field of Metamaterials is trying to be applied to similar applications. Although different, both technologies have some similitudes as it has been proven for different authors. For instance when working with EBG structures Left-Handed properties can be obtained in some frequency ranges. In this paper, research efforts focussed on applying EBG technology and the more recent Metamaterials, in particular, left-handed materials, to antenna subsystems at microwave and (sub)millimetre wave frequencies are introduced.
Open Access
A Chebyshev transformer-based microstri-to-groove-gap-waveguide inline transition for MMIC packaging
(IEEE, 2019) Pérez Escudero, José Manuel; Torres García, Alicia E.; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The gap waveguide technology has become an alternative to millimeter- and submillimeter-wave electronic circuit packaging thanks to the loss reduction associated with its use. In this paper, a simplified design of an inline transition between a microstrip and a groove gap waveguide (GGW) operating at the W-band is presented. The transition consists of a tapered microstrip line and a Chebyshev adapter that couple the quasi-TEM mode of the microstrip line to the so-called vertical mode of the GGW. The simplicity of this design makes this transition appropriate for monolithic microwave integrated circuit (MMIC) packaging at millimeter frequencies and above. The simulation results have been experimentally validated in the W-band. A good performance has been achieved, resulting in a return loss better than 10 dB and a mean insertion loss lower than 2 dB.
Open Access
Análisis de efecto de un superestrato left-handed en la apertura de una guía rectangular
(2005) Sáenz Sáinz, Elena; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Maagt, Peter de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, results showing the experimental verification of the gain improvement of a rectangular waveguide antenna when a left-handed material (LHM) is used as superstrate are presented. The improvement has been characterized by means of measuring the increase of transmission (S21 parameter) obtained when this LHM is placed between two open-ended rectangular waveguide antennas. An average increase of transmission of about 6.5 d.B has been obtained. Besides, improvements in the radiation patterns of a rectangular waveguide with a LH superstrate are analyzed. An enhancement of 3.5 dB in the directivity and a reduction of 15 dB in the back radiation have been obtained.
Open Access
Broadband radar cross-section reduction using AMC technology
(IEEE, 2013) Iriarte Galarregui, Juan Carlos; Tellechea Pereda, Amagoia; Martínez de Falcón, José Luis; Ederra Urzainqui, Íñigo; Gonzalo García, Ramón; Maagt, Peter de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This paper presents the design, fabrication and characterization of a planar broadband chessboard structure to reduce the radar cross-section (RCS) of an object. The chessboard like configuration is formed by combining two artificial magnetic conductor (AMC) cells. The bandwidth limitations intrinsic to AMC structures are overcome in this work by properly selecting the phase slope versus frequency of both AMC structures. 180 degrees phase difference has been obtained over more than 40% frequency bandwidth with a RCS reduction larger than 10dB. The influence of the incidence angle in the working bandwidth has been performed. A good agreement between simulations and measurements is achieved.
Open Access
Electromangetic force density in electrically and magnetically polarizable media
(American Physical Society, 2013) Liberal Olleta, Íñigo; Ederra Urzainqui, Íñigo; Gonzalo García, Ramón; Ziolkowski, Richard W.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The force density induced by electromagnetic fields in electrically and magnetically polarizable media is studied analytically. Different formulations of the force density as a function of field-related quantities, including the spatial derivatives of the fields, gradients of the field intensity, phase gradients, electromagnetic power flow (Poynting vector field), and kinetic momentum flow, are introduced. These formulations retain certain symmetries with respect to the force expressions introduced in previous works for an isolated particle but also point out fundamental differences, such as the suppression of recoil forces, negative radiation pressure, and far-field gradient forces. It is shown how these analytical formulations also provide the necessary means to elucidate the sign of the force density in complex media and how they can assist the design of sources to manipulate clouds of particles. The theory is illustrated with numerical examples of an insulated Hertzian dipole immersed in different media, including lossy dielectrics, media with negative permittivity and permeability, and zero-index media.
Open Access
A millimeter-wave 4th-harmonic Schottky diode mixer with integrated local oscillator
(MDPI, 2021) Pérez Escudero, José Manuel; Quemada Mayoral, Carlos; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this paper the design and experimental validation of a fourth-harmonic mixer based on Schottky diodes working around 300 GHz is presented. The main novelty of this work consists in the integration of an MMIC-based local oscillator, working around 75 GHz, and a mixer in the same metallic block housing. A prototype has been characterized using the Y-Factor method and yields a best measured conversion loss and an equivalent noise temperature of 14 dB and 9600 K, respectively. This performance is comparable to the state-of-the-art for this type of mixer.
Open Access
Near-field electromagnetic trapping through curl-spin forces
(American Physical Society, 2013) Liberal Olleta, Íñigo; Ederra Urzainqui, Íñigo; Gonzalo García, Ramón; Ziolkowski, Richard W.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Near-field electromagnetic trapping of particles is generally obtained bymeans of gradient forces. In this paper, we discuss the attractive behavior of curl-spin forces, as well as their potential for near-field electromagnetic trapping and manipulation. It is demonstrated that curl-spin forces enable the trapping of particles operating at their resonant frequency. Such phenomena can be exploited to design more efficient and selective electromagnetic traps, to boost near-field energy exchange systems, and to bring stability to coupled resonant radiators. It also is illustrated how the balance between the gradient, radiation pressure, and curl-spin force components leads to the formation of zero-force rings around their sources, which explicitly demarcate the trapping regions. Analytical and numerical analyses are presented to assess the stability of the trapping mechanism.
Open Access
Enhanced radiation properties of a rectangular waveguide by means of a left handed media
(2005) Sáenz Sáinz, Elena; Ederra Urzainqui, Íñigo; Gonzalo García, Ramón; Maagt, Peter de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, the results of experimental investigations to improve the gain between two antennas by means of a Left Handed Material (LHM) are presented. The basic idea is the use of a LHM media acting as a resonator to concentrate the power radiated by a rectangular waveguide achieving larger directivities and consequently larger gains. The transmission and radiation properties of this metamaterial (MTM) have been measured using a network analyser and two rectangular waveguides in the X band. Comparing the transmission parameter S21 with and without the LHM media between the waveguides, an appreciable improvement in the power received can be observed.
Open Access
Dipolos y metamateriales: mejora de las características de radiación
(2004) Sáenz Sáinz, Elena; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Maagt, Peter de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, pass band properties of Left Handed Media (LHM) are demonstrated. These properties have been used in order to make a LHM super-substrate that is put over a dipole antenna. This super-substrate is going to determine the characteristics of radiation patterns. Simulation with different types of configurations are presented in order to enhance the features of radiation patterns at bore-sight direction.