Programa del congreso

En este trabajo se describen los parámetros de diseño, pruebas experimentales y simuladas de un prototipo experimental ArcSAR (Arc-Scanning Synthetic Aperture Radar) embarcado en un vehículo aéreo no tripulado para detección de blancos mediante el escaneo de un entorno permitiendo la localización de estos y evitar posibles obstáculos. Este prototipo que trabaja en bandas milimétricas (24GHz), permite sintetizar la apertura del tamaño de una antena de gran diámetro, a partir del ancho del haz de una antena de diámetro pequeño, característica que le posibilita tener una alta resolución acimutal para discriminación de blancos muy cercanos unos de los otros.

A partir de la evolución y mejora de prototipos ArcSAR terrestres diseñados por el grupo de Microondas y Radar de la Escuela Técnica Superior de Ingenieros de Telecomunicación de la Universidad Politécnica de Madrid, se realizaron modificaciones en lo relacionado a reducción de tamaño, disminución de peso y mayor autonomía, parámetros necesarios para que el prototipo ArcSAR pudiera ser embarcado en un vehículo aéreo no tripulado, mejor conocido como DRON.

This paper presents a Nolen 4x4 matrix beamforming network using lumped elements in the overall matriz; the main application is for the ISM 900 MHz band. The matrix proposed develops a solution with space reduction and good performance. The methodology for design branch line couplers and phase shifters is based on equivalence between transmission lines and lumped elements and it is depicted in the first place. We

fabricated a first prototype to 920 MHz as central frequency and we assembled the matrix over Rogers 4003 Substrate in one layer with lumped elements SMD type of 1005 package. The results show agreement with simulated results, the bandwidth obtained

was approximately 7.3 %; about the radiation patterns over output ports indicate good results in terms of beam scanning. The overall matrix size is 11.4 x 4.1 cm. Hence, this feeding network has the correct behavior for a Nolen 4x4 matrix and the footprint is seven times smaller than if it were developed using microstrip technology.

In this work, the wireless channel was measured in the FR3 band (7 to 24 GHz) using a vector network analyzer and virtual antenna arrays in an indoor environment, under both line-of-sight (LoS) and non-line-of-sight (NLoS) conditions. Path loss values were extracted from measurements conducted at multiple locations across the entire band, as well as within selected sub-bands: 7.125–8.4 GHz, 10–10.5 GHz, 10.7–13.25 GHz, 14.8–15.35 GHz, 17.7–19.7 GHz, and 21.2–23.6 GHz. For each case, the floating-intercept path loss model was fitted. Additionally, a partition loss model was implemented to estimate attenuation under NLoS conditions.

This study presents a mostly experimental work which explores the capabilities of the orbital angular momentum (OAM) waves for near-field (NF) indoors communications in the FR2 regions. With this goal, a well-known T-shaped unit cell is used with a circuital model and analytical expressions where, by changing the ratio of dielectric to air, it is possible to generate the necessary phase shifts to produce OAM waves. Once the transmitarrays (TAs) are designed, several tests are conducted where the orthogonality and the capability of avoiding objects of OAMs is explored. For this purpose, thanks to stereolithography, TAs are 3D-printed in our facilities and measured the orthogonality of the modes with their E-field pattern and the ability to pass through objects.