Programa del congreso

This paper presents the analysis of a ubiquitous frequency modulated continuous wave (FMCW) radar system demonstrator, working at 8.75 GHz (X band). The main application of the system is the surface surveillance. This article presents the demonstrator and describes its main blocks. The document introduces the chosen scenario for field tests, and shows results of the offline processing illustrated with Range-Doppler matrix. This paper shows the active calibration procedure used to reduce unbalances between channels. The radar is a high range resolution system that performs the digital beamforming only on receive. To calibrate the system, an auxiliary rotating radiating source plus an electro-optical delay line are used

This paper presents preliminary results of recent HydroSoil radar continuous monitoring campaigns over agriculture fields. Future Radar Earth Observation missions with reduced revisit times will offer the capability to obtain valuable water cycle data applicable in agriculture and meteorology. Some of the phenomena involved have time scales much shorter than present satellite revisit times and for this reason are not well understood. HydroSoil measurements over barley and corn crops have provided valuable data to better understand air humidity and dew impacts on magnitude and phase of radar backscattering, which depends also on soil moisture and rain. Both barley and corn observations have shown a daily cycle magnitude ripple in the order of 1 to 3 dB caused by dew. Interferometric coherence has shown a strong dependence with plants height which can be exploited to sense the crop growth from radar observations

Current cardiopulmonary activity monitoring is based on contact devices which cannot be used in extreme cases such as premature infants, burnt victims or rescue operations. In order to overcome these limitations, the use of radar technologies emerges as an alternative. This paper aims to enhance the comprehension that non-contact technologies, in particular radar techniques, offer as a monitoring tool. For this purpose, a modified low cost commercial 122 GHz frequency-modulated continuous-wave (FMCW) radar is used to better fit the current application domain. The radar signals obtained are processed using a classic linear filtering algorithm aiming to separate the breathing from the heartbeat component while preserving signals integrity. In a standoff configuration and with different subject orientations, results show that the signal obtained with the radar can be used to extract not only the respiratory and heartbeat rates, but also the heart rate variability (HRV) sequence. Moreover, results evidence the coupling between breathing and heartbeat, also showing that the HRV sequence obtained can identify the respiratory sinus arrhythmia (RSA) effect. Finally, the radar is tested in a simultaneous multi-target scenario, demonstrating its monitoring capabilities in more complex situations. Nevertheless, there are some challenges left to use the system in a real-life monitoring environments, such as the removal of random body movements.

En este artículo se comparan una estructura de tablero de ajedrez periódica basada en rotaciones seleccionadas de un elemento CSSR (anillos resonantes divididos en forma de C) con una estructura no periódica basada en rotaciones aleatorias del elemento CSSR, ambas para reducir la RCS. En ambas estructuras se combina la diferencia de fase de 180º entre elementos a partir de las diferentes rotaciones del elemento CSSR junto con la rotación de polarización. Posteriormente, se comparan las mismas estructuras añadiendoles con un elemento absorbente RFSS Square Ring.

This paper presents a cavity-fed double-slot antenna array in SIW technology at millimeter-waves frequencies. The double slots allow better control in the designed frequency band regarding the single slots. To demonstrate this fact, a brief performance comparison between the two implementations are shown. The prototyped antenna contains 4 cavity-backed subarrays in one SIW-layer where each cavity has in its corners the double-slots therefore, we achieve a 4x4 array. To feed all the cavities, a corporate network is used. At the outputs of the feeding network, the power is coupled through rectangular apertures to the cavity-backed antennas. The manufactured antenna array experimentally provides a bandwidth from 35.4 GHz to 37 GHz. There is good agreement between simulated and measured results, with a stable measured gain about 17 dBi along the frequency band.

Ongoing

ongoing

Recientemente ha habido un creciente interés por la gestión de la red eléctrica debido a la preocupación por el calentamiento global. Con el avance en la industria de vehículos eléctricos (EV) y la evolución de las baterías, los EV se convierten en un contribuyente importante a la red con capacidad de intercambio bidereccional de energía. En este contexto, los sistemas Vehicle-to-Grid (V2G) permiten múltiples funcionalidades entre los vehículos eléctricos y el agregador correspondiente. Por lo tanto, es importante contar con capacidades de comunicación confiables y de largo alcance entre el agregador y dichos vehículos eléctricos. En este trabajo se presenta el análisis del canal radio para la comunicación entre el agregador y el vehículo eléctrico, utilizando la tecnología Long-Range Wide Area Network (LoRaWAN), con el fin de probar una solución de bajo coste con gran cobertura y perfil de consumo de energía reducido. Se han realizado medidas de canal inalámbrico en un escenario urbano real entre una estación de carga de EV localizada en Pamplona y un vehículo en movimiento utilizando dispositivos LoRaWAN a 868 MHz. La caracterización del canal inalámbrico se ha llevado a cabo mediante la implementación de un modelo de escenario urbano completo en 3D, que incluye elementos como edificios, vehículos, usuarios e infraestructura urbana como postes de luz y bancos. Mediante el algoritmo de lanzado de rayos 3D (3D-RL) desarrollado íntegramente en la UPNA, se han obtenido estimaciones de la distribución de potencia RF, SNR y análisis temporal para el volumen completo del escenario. La comunicación V2G de extremo a extremo se ha validado mediante la implementación de un sistema de recopilación de datos dentro del vehículo: Controller Area Network-BUS (CAN BUS) conectado al transceptor LoRaWAN del vehículo y, posteriormente, a un servicio web en la nube. Los resultados muestran que el análisis determinista permite optimizar el diseño de las redes LoRaWAN en un entorno vehicular, considerando enlaces entre vehículos e infraestructura, lo que permite un intercambio de datos escalable y de bajo coste de extremo a extremo para el despliegue de servicios V2G auxiliares.

This contribution presents an analysis of radio propagation in wireless context-aware environments, such as auditoriums, for the implementation of an Augmented Reality (AR) system dedicated to help and improve the user experience of people with disabilities in auditoriums. To evaluate the proposed system, an evaluation of the wireless channel has been carried out in Baluarte Palace of Congresses and Auditorium of Navarre. In order to show the behavior of the radio channel, simulations have been carried out using a deterministic 3D Ray Launching algorithm developed, as well as RF signal propagation measurements, with the aim of analyzing the impact of the scenario morphology and the presence of human bodies. The results obtained provide useful guidelines for deploying novel AR systems in scenarios as complex in terms of wireless propagation as large auditoriums. As an example, an AR application has been developed for Microsoft HoloLens capable of helping people with hearing disabilities during shows at the Baluarte Auditorium.

En este trabajo se pretende simular y analizar dos técnicas de acceso basadas en la geolocalización para la comunicación entre vehículos. Los vehículos se generan mediante Procesos Punto de Poisson y se estudia la Relación Señal a Ruido más Interferente para dos tipos de mensajes a transmitir y sobre un escenario urbano. A partir de dicha relación, se puede obtener la probabilidad de cobertura, el régimen binario y la eficiencia energética de ambas técnicas de acceso. Los resultados reflejan la importancia de la asignación de recursos para un escenario urbano, así como su tamaño.

An upgraded version of the complementary strip-slot radiating element is reviewed. The original radiating element consists in a microstrip-fed slot in transmission cofiguration. In the proposed modification, the slot is backed by a cavity in order to obtain unidirectional radiation. The presence of this cavity changes the behavior of the slot. A new equivalent circuit is used to propose a design methodology for broadband operation. Two array designs are simulated and implemented: a phased array and a log-periodic array. Promising experimental results verify the unidirectional radiation and the wide bandwidth of these antennas.

The authors propose a circuit methodology for the design of broadband stacked microstrip antennas fed through an aperture. An equivalent circuit (EC) is introduced for the antenna, which consists of an LC series resonator (the feed) plus two capatively coupled LC parallel resonators (the stacked patches). The circuit parameters are determined in terms of antenna simulations by means of a numerical de-embedding procedure. Then, the stage of the EC representing the two patches is designed using a circuit topology that implements a non-standard quasi-Chebyshev second order bandpass filter response. This non-standard topology enables a design of stacked microstrip antennas with bandwidths in excess of 30% by simply stacking one rectangular patch above another rectangular patch with inner and meandering slots. A prototype of the antenna has been fabricated and measured. Good agreement has been found between simulation and measurements for the return losses and the radiation patterns.

En este trabajo se estudiará el diseño de una agrupación de ranuras en banda K con una alimentación por onda progresiva proporcionada por la tecnología de guía de onda integrada en sustrato, más conocida como Substrate Integrated Waveguide (SIW). Las antenas con alimentación tipo serie o por onda progresiva proporcionan grandes ventajas tales como una gran compacidad estructural (en comparación con las redes de alimentación corporativas), banda ancha o altas prestaciones en cuanto a ganancia y eficiencia. Además, según aumenta la frecuencia este tipo de antenas son capaces de implementar un desapuntamiento del haz principal de radiación que puede ser interesante en diversas aplicaciones.

Sin embargo, normalmente las antenas de onda progresiva presentan cambios rápidos de su capacidad de acoplo con la frecuencia. Esto se traduce en que, si las especificaciones de eficiencia o de estabilidad del diagrama de radiación en banda de nuestro diseño son muy exigentes, puedan no cumplirse. Dicho de otro modo, el comportamiento típico en banda de las antenas de este tipo puede reducir el ancho de banda efectivo de la antena. Por tanto, en este trabajo se ha diseñado una antena de tipo array plana que proporcione alta ganancia, así como un incremento del ancho de banda efectivo de la antena en términos de radiación y eficiencia.

In this paper, a compact dual-feed annular ring patch antenna that covers two 5G millimeter-wave bands is presented. The bandwidths covered are the n258 (24.25 - 27.5) GHz and the n260 (37 - 40) GHz with polarization diversity due to the inclusion of a dual-feed aperture-coupled system.

This paper presents a Planar Inverted-F Antenna (PIFA) design for a smartwatch application, optimized to operate on the 2.4 GHz Bluetooth frequency band, on the proximity of the human forearm. The PIFA antenna is mounted on the watchstrap that is used as the antenna substrate. The antenna is fed in a singular way, since a coplanar wave-guide (CPW) transmission line is used to excite the antenna. The antenna is integrated in the watchstrap, curved over the phantom forearm and simulated along with the watchcase. A return loss of –20 dB is obtained at 2.4 GHz, and an efficiency of -5 dB, which represents a good efficiency taking into account the effect of the human forearm.

Serrated reflector systems are widely used in com-pact range antenna measurement (CATR) setups. Besides max-imizing the size of the reflector, serrations are essential forimproving the size and quality of quiet zones. Multiple serrationgeometries are available in the literature but, for the most part,there seems to be no evident relationship between the char-acteristic parameters of these geometries and their implicationin quiet zones’ size and quality. Optimization algorithms andcomparison metrics are needed in order to reach an optimumedge serrations geometry. This work presents a method tooptimize an offset reflector system that can be generalized toany CATR reflector setup.

In this paper we present a broadband circularly polarized low profile metasurface (MTS) antenna. A metasurface of 3x4 rectangular cells is first analyzed using characteristic mode analysis (CMA). As a result, two modes with orthogonal current distribution and almost 90º phase difference are selected to contribute to the circular polarization radiation.

Finally, an appropriate rotated coplanar waveguide (CPW) feeding line is chosen to excite the two modes. The simulation results show 3-dB axial ratio band of 13.8% (5.6-6.43GHz), an impedance bandwidth of 24.1%, and a peak gain of 8dBi. The dimensions of the proposed design are 1.0λ0×1.0λ0×0.059λ0.

RF energy harvesting through the use of rectennas, an element with which DC power is obtained from electromagnetic waves found in free space, is currently gaining momentum as new designs are being proposed. The state of the art of harvesting is mostly focused on the design of single-band rectennas. However in this paper, a multi-tone system has been designed where several frequency bands will be collected. The design of the proposed rectenna is based on both short-circuited patch antenna and Crofton-Walton rectifier. The simulation results are shown, obtaining really good efficiency and reflection coefficient values. The main conclusion reached in this work is that a multi-tone system is more challenging than a single-frequency system with advantages such as higher DC output voltage, efficiency and diversity.

Este artículo propone una antena de cuatro puertos con respaldo de cavidad de banda ancha para aplicaciones de estaciones base interiores. La antena está compuesta por una cavidad abierta de forma cuadrada con un bloque aislante en forma de X situado en el centro y 4 monopolos dispuestos de forma simétrica en la apertura de la cavidad. Para su diseño se ha utilizado una metodología basada en el análisis de modos característicos (CMA) para identificar los modos que contribuyen al acoplamiento y justificar el uso del bloque en forma de X para incrementar el aislamiento entre puertos. La antena dispone de cuatro diagramas de radiación unidireccionales y un ancho de banda (S₁₁<-10 dB) que opera desde 1.55 GHz hasta 6 GHz (118%), cubriendo la mayoría de las bandas 5G sub-6 GHz. El aislamiento entre puertos es de mínimo 16 dB y la eficiencia superior al 84%. La antena es de fácil fabricación y presenta un tamaño compacto de 129.5 x 129.5 x 28.2 mm³ (0.68λ x 0.68λ x 0.15λ, a la frecuencia mínima f=f_min=1.55 GHz).

A circularly polarized implantable antenna (CPIA)

working at industrial, scientific, and medical (ISM) band (915)

MHz is presented in this communication. The proposed CPIA

consists of a meandered line surrounded by a U-structure

to guarantee circular polarization. With this combination, we

achieve a wideband axial ratio (AR) of 27 % from 770 to

1010 MHz, and a wideband reflection coefficient of 20 % from

809.4 to 989.8 MHz. Moreover, 12 m distance communication

is guaranteed for a link margin of about 30 dB. The antenna

has a compact size of 0.01 × 0.01 λ<sup>2, which makes it a good

candidate for implantable devices.

In this work, the corona discharge thresholds in microstrip bandpass filters (BPFs) are studied, and a new design strategy is proposed for enhancing the peak power handling capability (PPHC). For this purpose, we suggest a new topology based on circled-end resonators to achieve a reduction of the maximum peak voltage (Vpeak) and avoid sharp corners. First, a theoretical analysis is carried out to obtain an expression for modeling the reduction of Vpeak. Next, a second study shows the variation of the PPHC for different sizes of the rounded-ends. Finally, the effectiveness of the proposed solution is validated by means of experimental measurements, showing a PPHC enhancement of 2.10 dB compared to a conventional microstrip BPF with rectangular-end resonators.

The use of 3D printed technology for designing wideband flat lenses is

explored in this work. Different types of lenses are analyzed, all of

them with wideband characteristic in the Ka band. The design of these

graded index lenses is made using different commercial filaments and

playing with different infill percentages always taking into account as

well mechanical limitations. A study of their performance when scanning

the beam is also presented. Some prototypes have been manufactured and

measured showing an excellent performance including low loss

characteristic in this high frequency band.

Multi-feed shaped-beam perforated dielectric transmitarray in millimeter-band

Design of a Fresnel lens at 60GHz

Gallium arsenide (GaAs) metamorphic high electron mobility transistors (mHEMT) and a grounded coplanar waveguide environment offer remarkable electronic properties, placing them into a key position for millimeter wave (mmW) and sub-mmW power amplifiers (PAs). At these high frequencies it is a great challenge to obtain accurate models that predict the real performance of the active components (i.e. transistors). This paper presents an experimental validation of a cascode configuration based on a multiport transistor model. The inhouse model shows very high accuracy for measurements in a broad range of frequencies (0.1 - 330 GHz). The good correlation of the simulation of the model and the posterior measurements was verified by the fabrication of a G-band (140 - 220 GHz) PA module. The packaged PA showed a small-signal gain of more than 13.4 dB for a broad bandwidth of 56 % and a maximum output power of 4.61 dBm at 210 GHz.

In this work, we develop a novel Monte Carlo method for solving the electromagnetic scattering problem. The method is based on a formal solution of the scattering problem as a modified Born series whose coefficients are found by a conformal transformation. The terms of the Born series are approximated by sampling random elements of its matrix representation, computed by the Method of Moments. Unlike other computational techniques, this Monte Carlo method does not require communications between processors, which makes it suitable for large parallel executions.

A gradient index flat lens with a directive beam-steering radiation pattern and configurable dual circular polarization is discussed in this contribution. The dielectric lens, designed to operate at W band (70-100 GHz), is perforated to achieve a radial decreasing dielectric permittivity characteristic, so high-directivity beam with planar wave front can be obtained. A precisely designed stereolithography 3D structure is adhered to the surface of the lens to turn the vertical or horizontal electric field polarization into RHCP or LHCP, respectively. An open-ended square waveguide is used as feeding structure in order to generate the vertical and horizontal polarization by the excitation of the degenerate modes TE10 and TE01. The system can achieve a wide beam-steering range of ±30° in both azimuth and elevation planes, attained by applying precise displacements to the feeding square waveguide position. In order to experimentally validate the antenna performance, the design is fabricated and measured.

New telecommunication and radar systems at high frequencies require high directive antennas with low scan losses to compensate the path loss and propagation attenuation. Geodesic lens antennas are a good candidate to these new applications since they can provide high directivity, high efficiency and low scan losses. Here, we explain how to produce rotationally symmetric geodesic lenses based on transformation optics. In particular, we calculate the equivalent geodesic shape of a Luneburg lens, which is able to transform cylindrical waves into planar waves. In order to demonstrate the potential of this technique, we designed a 11-port geodesic lens antenna, which is able to scan 120º. The beams have a maximum gain of 20 dB at 30 GHz with 0.5 dB scan losses. We describe possible manufacturing techniques, including their advantages and drawbacks in terms of assembly misaligments, surface roughness and tolerances.