Open Access
A wide beamwidth magneto-electric dipole atenna for wide beam scanning antenna arrays
(IEEE, 2024-09-30) Khan, Ihtesham; Zhao, Huiling; Iriarte Galarregui, Juan Carlos; Ederra Urzainqui, Íñigo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
In this study, a simple and cost-effective configuration to broaden the beamwidths of the patch antenna has been studied. The proposed wide beamwidths antenna consists of two parasitic magnetic dipoles placed orthogonally to a driven electric dipole. Due to the complementary far-field radiation behaviors of both antennas in their respective E-plane and H-plane, the antenna half-power beamwidth broadens. An excellent wide beam of 138.6° and 110.9° in E-plane and H-plane, respectively, has been achieved at 4.72 GHz. The proposed antenna has been fabricated and tested. Measurements shows good agreement with the simulations. The proposed antenna can find its application for the increasing the scanning coverage of the patch antenna arrays.
Open Access
Surface waves of finite size electromagnetic band gap woodpile structures
(EMW Publishing, 2011) Ederra Urzainqui, Íñigo; Iriarte Galarregui, Juan Carlos; Gonzalo García, Ramón; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This paper studies the surface modes at the interface of finite size Electromagnetic Band Gap (EBG) woodpile structures. The impact of different types of woodpile terminations on the properties of these surface modes is analyzed. For all the studied terminations there exist surface modes which must be taken into account when designing components based on this EBG structure.
Open Access
EBG superstrate antenna for WAAS bands
(2008) Osés de León, Ángel; Iriarte Galarregui, Juan Carlos; Ederra Urzainqui, Íñigo; Gonzalo García, Ramón; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Multiband antennas can simplify considerably the complexity of receivers and transmitters, reducing the size and the mass of the conventional configurations. On the other hand, applications with high directivity requirements need array designs to comply with the directivity specifications using conventional technology. EBG superstrate designs have been satisfactory applied to single band applications using a single EBG superstrate layer. The number of number of radiating elements of conventional technology designs are considerably reduced when using EBG technology. Dual band configurations have also been designed in a single layer, but when working frequencies are too close a second EBG layer is needed. A dual layer EBG superstrate which can easily be adjusted to the desired operational frequencies is presented. The design has been realized to comply with the navigation antenna requirements of Wide Area Augmentation system (WAAS) application in L1 and L2 bands.
Open Access
Assessment of mm-wave high resolution inverse SAR imaging both with compact and sparse data
(IEEE, 2023) Iqbal, Muhammad Amjad; Anghel, Andrei; Datcu, Datcu; Ederra Urzainqui, Íñigo; Iriarte Galarregui, Juan Carlos; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
Inverse synthetic aperture radar (ISAR) provides images of objects that are rotated with respect to the radar. An efficient image-focusing algorithm is required to generate ISAR images from the echoes of the raw data. In this study, a monostatic model was deployed to collect radar backscattering data in the millimeter (mm) wave band (67-110 GHz) using targets with circular, rectangular, and non-canonical shapes. The ISAR experiments were performed to assess the imaging performance of the three methods. The ISAR image reconstruction implemented in the wave-number (¿ - k) domain solves the target reflectivity and allows the target to be close to the radar. This shows that the mm-wave radar can achieve a sufficient resolution in the range and azimuth dimensions. Finally, we compared the results with those of spherical wavefront compensation (SWFC) and back-projection (BP) methods. The efficiencies of the three methods were tested using compressible data with wavelet-decomposition-based sparse measurements. To demonstrate the performance of the given methods, the point spread function (PSF) for the impulse response of the mm-wave wire was computed. There is a trade-off: the ¿ - k domain loses resolution compared to the SWFC and BP methods but can obtain a satisfactory image at a lower computational cost.
Open Access
Moisture content estimation models of flour matrices in the 67-110 GHz frequency range using a nondestructive and contactless monitoring system
(IEEE, 2023) Quemada Mayoral, Carlos; Ederra Urzainqui, Íñigo; Beruete Díaz, Miguel; Gonzalo García, Ramón; Iriarte Galarregui, Juan Carlos; Estadística, Informática y Matemáticas; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Estatistika, Informatika eta Matematika; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This work addresses the lack of moisture content estimation models for food products in the millimeter-wave frequency range and showcases the potential of this range for designing compact, cost-effective, and in-line food moisture sensors. The moisture content estimation models developed in this study are intended for flour-based mixtures in the 67-110 GHz frequency range and are derived by means of a nondestructive and contactless monitoring system. To this aim, data obtained by continuous-wave (CW) vector network analyzer (VNA) spectroscopy is used to create two different models, both with a coefficient of determination ( R2 ) of 0.97. One model is based on the theoretical response obtained by means of the Looyenga effective medium theory (EMT) model, while the other is based on measured data. Both models have been experimentally validated with root mean square error (RMSE) values of 0.4% and 0.35%, respectively. These small estimation errors show the potential of this frequency range to design compact, cost-effective, and in-line food moisture sensors. This research contributes to improving quality control and monitoring of moisture levels in flour-based mixtures.
Open Access
Wideband circularly-polarized gap waveguide-based antenna design
(IEEE, 2025-03-12) Leoz-Beltrán, Iñigo; Iriarte Galarregui, Juan Carlos; Pérez Quintana, Dayan; Teberio Berdún, Fernando; Beruete Díaz, Miguel; Ederra Urzainqui, Íñigo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
This paper presents the design of an all-metal antenna based on Gap Waveguide technology. The antenna, which is realized using a Ridge Gap Waveguide, consists of just two layers, maintaining a compact size. The first layer is made up of two perpendicularly placed arms, which comprise the feeding, and the second layer hosts a diamond shaped slot and a horn, which comprise the radiator. Simulations show that the design achieves a remarkable bandwidth equivalent to the 31.43% of the central frequency in terms of both S11 parameter, being below -10 dB, and Axial Ratio, being below 3 dB.
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
Design alternatives for a submillimeter-wave Fabry-Perot cavity antenna with a SiGe on-chip feed
(IEEE, 2024-02-17) Iriarte Galarregui, Juan Carlos; Khan, Ihtesham; Herrera-Martin, Juan M.; Urain, Álvaro; Berenguer, Roc; Ederra Urzainqui, Íñigo; González Posadas, Vicente; Segovia-Vargas, Daniel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PRO-UPNA 11893
In this paper different alternatives for the design of a Fabry-Perot cavity antenna operating in the Sub-mmwave frequency range and fed by a SiGe spiral antenna are evaluated. In particular a single spiral and a sequentially fed array of spiral antennas are compared, showing, due to the losses in the Si substrate the superior performance of the single fed cavity. However, the use of a sequentially rotated array significantly improves the Axial Ratio (AR).
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
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.