Open Access
New hexagonal CORPS-BFN for multibeam antenna applications
(IEEE, 2020) Biurrun Quel, Carlos; Montesano, Antonio; Ederra Urzainqui, Íñigo; Iriarte Galarregui, Juan Carlos; Río Bocio, Carlos del; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This work presents a new topology of a Coherently Radiating Periodic Structure - Beam Forming Network (CORPS-BFN) and its application for multibeam systems. A unit cell, consisting of a transition from a coaxial input to an intersection of three strip-lines with an angular span of 120 degrees, is proposed and analysed. A periodical replication of the cell gives rise to a uniform layer, allowing a proper matching of the ports of the network. Stacked layers allow in-phase propagation and distribution of the energy through the structure, increasing the number of output ports with each layer.
Open Access
Planar DNG superstrate for dipole antenna gain enhancement
(2007) Sáenz Sáinz, Elena; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Ikonen, Pekka; Tretyakov, Sergei A.; Maagt, Peter de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, a volumetric double-negative (DNG) superstrate based on grids of dipoles and wires for dipole antenna applications is proposed.
Embargo
Experimental validation of a Ku-band dual circularly polarized metasurface antenna
(IEEE, 2018) Tellechea Pereda, Amagoia; Caminita, Francesco; Martini, Enrica; Ederra Urzainqui, Íñigo; Teniente Vallinas, Jorge; Iriarte Galarregui, Juan Carlos; Gonzalo García, Ramón; Maci, Stefano; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
The experimental validation of a Ku-band dual circularly polarized (CP) broadside-beam metasurface (MTS) antenna is presented. A radially modulated anisotropic single layer MTS has been synthesised employing sub-wavelength elliptical slotted metallic patches printed on top of a thin Arlon grounded substrate. In the structure, two decoupled phasematched transverse magnetic and transverse electric surface waves (SWs) are excited, which interact with the modulated surface leading to a CP broadside radiation. Two different orthomode transducers have been designed to excite the SWs with orthogonal polarization and equal amplitude. The first feeding system is composed of a metallic stepped septum inside an airfilled square waveguide. A conical section is included to match the output port of the square waveguide with the terminal, dielectric filled circular waveguide. The second feed is much more compact and efficient and it is composed of a circular waveguide completely filled by a dielectric. Depending on the input port excited on the feeds, two TE11 modes are excited with ±90° phase shift, which determine the right-hand or left-hand sense of the broadside beam generated by the MTS. Manufacturing details of the MTS and excitations are given and the measurements are compared with the simulation results. Finally, conclusions are drawn.
Open Access
Induction theorem analysis of resonant nanoparticles: design of a huygens source nanoparticle laser
(American Physical Society, 2014) Liberal Olleta, Íñigo; Ederra Urzainqui, Íñigo; Gonzalo García, Ramón; Ziolkowski, Richard W.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We propose an advanced formulation of standard antenna theory for the basic investigation and design of resonant nanoparticles. This methodology is based on transforming the original scattering problem into a radiation configuration by invoking the induction theorem. Then applying basic antenna theory principles, such as the suppression of any reactive power, the properties of the resonances are engineered. This nanoantenna approach has been validated by revisiting a number of well-known multilayered core-shell structures. It provides additional important physical insights into how the core-shell structures operate and it enables combinations of different resonant phenomena associated with them, e.g., plasmonic and high-ϵ resonances, in an intuitive manner. Its efficacy is demonstrated by designing a multilayered nanoparticle that achieves lasing with a maximum directivity in the forward direction and a null in the backward direction, i.e., a Huygens source nanoparticle laser.
Open Access
Fully metallic Luneburg metalens antenna in gap waveguide technology at V-band
(IEEE, 2023) Pérez Quintana, Dayan; Bilitos, Christos; Ruiz-García, Jorge; Ederra Urzainqui, Íñigo; Teniente Vallinas, Jorge; González-Ovejero, David; Beruete Díaz, Miguel; Institute of Smart Cities - ISC
This article presents the design of a flat Luneburg metalens antenna at V-band using gap waveguide (GW) technology. The metalens consists of a parallel plate waveguide (PPW) loaded with metallic pins whose height is modulated to get an effective refractive index that follows the Luneburg equation. A Groove GW (GGW) H-plane horn is used to illuminate the metalens, such that the rays are collimated and a planar wavefront is generated in the direction of propagation. Since the structure at hand is planar, it can be efficiently integrated on flat surfaces. Moreover, the fully metallic structure is mechanically robust and presents lower losses than lenses including dielectric substrates. A prototype has been fabricated and tested, simulations and experimental results are in very good agreement. The metalens yields an input reflection coefficient (S11) below −10 dB from 45 to 70 GHz, whereas the −3 dB gain fractional bandwidth is 26.2% with respect to a center frequency of 60 GHz, with a peak of 22.5 dB at 61 GHz. These features make this design an interesting solution for millimeter-wave (MMW) applications.
Open Access
Design of a planar meta-surface based on dipoles and wires for antenna applications
(2006) Sáenz Sáinz, Elena; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Maagt, Peter de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, the design of a planar meta-surface based on dipoles and wires is presented. The unit cell is formed by three independent layers, which contain two parallel dipoles and one wire. The behaviour of these elements have been analysed separately as an independent unit cell, i.e., the one dipole unit cell, the two dipoles unit cell and the two dipoles and wire unit cell, by means of the transmission response and the dispersion diagrams. For a normal incident plane wave with the E field parallel to the wires and the H field axial to the dipoles, the electric and magnetic responses are excited producing a pass band behaviour which exhibit negative refractive index. This cell has been used to create meta-surfaces for antenna applications. Two configurations have been analysed; the first one is a superstrate of a dipole antenna with the pass band tuned to the resonant frequency of the dipole. It has been observed that the power goes through the meta-surface and is radiated mainly in boresight direction, which increases the directivity up to 8 dBi and the aperture efficiency of the whole configuration. In the second case, a substrate with the stop band tuned to the pass band of the superstrate and the resonant frequency of the dipole has been added. A directivity higher than 9 dBi with a back radiation of -20 dBi have been obtained.
Open Access
Evaluation of mutual coupling between slots in a metasurface enhanced SIW slotted antenna
(IEEE, 2023-10-26) Chocarro Álvarez, Javier; Ederra Urzainqui, Íñigo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
In this paper, we explore the conductance properties of a longitudinal slot on a substrate integrated waveguide (SIW) with three different models. These models allow us to evaluate the impact on the slot conductance of covering it with a metasurface to improve the radiation performance. In particular, the influence of the MTS on the coupling between slots will be analyzed. Our results show that the presence of the MTS reduces the slot conductance and slot resonance length, but has limited impact on the coupling.
Open Access
A water content continuous monitoring of grapevine xylem tissue using a portable low-power cost-effective FMCW radar
(IEEE, 2019) Quemada Mayoral, Carlos; García González, Cebrián; Iriarte Galarregui, Juan Carlos; Marín Ederra, Diana; Gastón Beraza, Diego; Miranda Jiménez, Carlos; Gonzalo García, Ramón; Maestrojuán Biurrun, Itziar; Santesteban García, Gonzaga; Ederra Urzainqui, Íñigo; Agronomia, Bioteknologia eta Elikadura; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Agronomía, Biotecnología y Alimentación; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua, PI025 VITHZ; Gobierno de Navarra / Nafarroako Gobernua, 0011-1365-2016-000084 RAFF
This paper presents the real-time monitoring of a grapevine’s water content that flows up through the xylem tissue by means of a frequency-modulated continuous-wave (FMCW) radar. The application of an optimization process, based on the super-resolution multiple signal classification (MUSIC) algorithm, has enabled the reduction of the bandwidth required to discern the xylem water content, and thus the operating frequency, achieving a depth resolution of at least 3 mm. This design advantage has resulted in a significant step forward towards a real life application, allowing the use of fully-integrated off-the-shelf components in order to implement a completely portable low-power cost-effective radar at 23.1 GHz with a 3.4 GHz bandwidth. The sensor performance has been evaluated by means of three different experiments: irrigation cycles, day/night cycles and comparison between irrigation cycles at different temperatures. From the experimental results, it is possible to assert that the contactless sensor presented in this work is very sensitive to changes in the plant’s water content, differentiating between daytime and nighttime. In addition, it has been proved that temperature has a noticeable influence over the evapotranspiration, observing negative drying slopes of 5.62 mV/cycle and 6.28 mV/cycle at 23ºC and 26ºC respectively.
Open Access
Silicon integrated subharmonic mixer on a photonic-crystal platform
(IEEE, 2021) Torres García, Alicia E.; Pérez Escudero, José Manuel; Teniente Vallinas, Jorge; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This paper presents a planar silicon integrated subharmonic mixer on top of a photonic-crystal platform. The local oscillator (LO) power is injected through a 2D photoniccrystal (PC) slab to a resonant cavity that effectively couples the signal to a planar bow-tie antenna. The same antenna, which is printed on the top of the PC cavity, contains an antiparallel Schottky diode pair which performs the down-conversion. The proposed design is a simple, easy to integrate, low cost, low profile device. Moreover, the described fabrication process is compatible with active components integration. The performance of the design has been experimentally demonstrated showing good agreement with the simulation and is comparable with the stateof-the-art of planar mixers. The work presented here is based on concepts and technologies from electronics and photonics domains and may be a good starting point for the creation of new devices, allowing the integration and upgrading of existing techniques from both worlds.
Open Access
A multipolar analysis of near-field absorption and scattering processes
(IEEE, 2013) Liberal Olleta, Íñigo; Ederra Urzainqui, Íñigo; Gonzalo García, Ramón; Ziolkowski, Richard W.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
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 that would be achieved by an ideal lossless sensor, which are of particular interest, for example, to wireless power transfer (WPT), wireless sensors and near-field coupled radiators. The multipolar formulation also helps to extricate the fundamental compromises that must be addressed in the design of such systems, as well as to identify strategies that could approach their best possible performances. The general theory is illustrated with an example consisting of a coated sensor illuminated by a Hertzian dipole, which is a representative example of any scattering or radiating system based on small resonators. The example also serves to compare the performance characteristics obtained with different phenomena such as multipolar resonances, phaseinduced interference effects and cloaking.