3x3 Multibeam Network for a Triangular Array of Three Radiating Elements

A multibeam antenna study based on Butler network will be undertaken in this document. These antenna designs combines phase shift systems with multibeam networks to optimize multiple channel systems. The system will work at 1.7 GHz with circular polarization. Specifically, result simulations and measurements of 3 element triangular subarray will be shown. A 45 element triangular array will be formed by the subarrays. Using triangular subarrays, side lobes and crossing points are reduced

Simultaneous detection of the spin-Hall magnetoresistance and the spin-Seebeck effect in Platinum and Tantalum on Yttrium Iron Garnet

The spin-Seebeck effect (SSE) in platinum (Pt) and tantalum (Ta) on yttrium iron garnet (YIG) has been investigated by both externally heating the sample (using an on-chip Pt heater on top of the device) as well as by current-induced heating. For SSE measurements, external heating is the most common method to obtain clear signals. Here we show that also by current-induced heating it is possible to directly observe the SSE, separate from the also present spin-Hall magnetoresistance (SMR) signal, by using a lock-in detection technique. Using this measurement technique, the presence of additional 2nd order signals at low applied magnetic fields and high heating currents is revealed. These signals are caused by current-induced magnetic fields (Oersted fields) generated by the used AC-current, resulting in dynamic SMR signals.Comment: 9 pages, 6 figure

Synthesis of circularly polarized radial line slot array

In previous articles, an easy way to analyse a slot array fed through a radial line was presented. The analysis was based on a circuit approach where circuit parameters have been estimated using the first propagation mode in the radial line and the far field theory. Here we study the design of a particular application for circularly polarised broadside antenna. The design defines the length, position and orientation of the slots in the antenna surface. The final analysis of the antenna gives a good behaviour in field diagrams and gain

Análisis, diseño y realización de antenas planas ranuradas multisatélite

A review of designs of linearly polarized parallel-plate slot antennas developed by the authors is presented. Different combinations are described: broadside beam, one and dual tilted-beam, one and dual polarized antennas. The antenna structure, the analysis methods and the feasibility of getting a dual beam and dual linearly polarized antenna with interesting characteristics and low cost are analyzed. Several designs are proposed and their features are studied. As a conclusion, it can be said that parallel- plate slot arrays are quite promising

Diseño y construcción de antena plana de doble polarización basada en ranuras para recepción de TV por satélite

In this paper we design and make a double-polarization plane slot antenna for Digital Television Satellite reception. The prototype will fulfil the DVB specifications and furthermore it should be simple to construct and cheap. Therefore in the design process and in the implementation process exists a compromise between the specifications, low costs and simplicity

Origin of inverse Rashba-Edelstein effect detected at the Cu/Bi interface using lateral spin valves

The spin transport and spin-to-charge current conversion properties of bismuth are investigated using permalloy/copper/bismuth (Py/Cu/Bi) lateral spin valve structures. The spin current is strongly absorbed at the surface of Bi, leading to ultrashort spin-diffusion lengths. A spin-to-charge current conversion is measured, which is attributed to the inverse Rashba-Edelstein effect at the Cu/Bi interface. The spin-current-induced charge current is found to change direction with increasing temperature. A theoretical analysis relates this behavior to the complex spin structure and dispersion of the surface states at the Fermi energy. The understanding of this phenomenon opens novel possibilities to exploit spin-orbit coupling to create, manipulate, and detect spin currents in two-dimensional systems

Blooms de cianobactérias tóxicas comprometem o uso da água do Rio Negro, Uruguai

Toxic cyanobacterial blooms generate negative environmental, economic and health impacts. We carried out an analysis of historical limnological data (1989-2020, n = 423) and we performed a nutrient enrichment experiment to study the cyanobacteria of Río Negro, the largest internal river of Uruguay. We defined four hazard levels of exposure to toxic cyanobacteria based on quantitative indicators (biovolume and abundance of cyanobacterial cells and visual observation). The most common cyanobacteria (Microcystis sp. and Dolichospermum sp.) are potential producers of various toxins, including some that have not yet been analyzed in Uruguay. Accelerating environmental deterioration since 2000 has been caused by an increase of cyanobacteria biomass and concentrations of toxins (microcystins). Nutrient concentrations indicated advanced eutrophication, associated with the increase in the area devoted to agriculture of ​​the watershed. Experimental results demonstrated the key role of nutrients and residence time in favoring these organisms. Toxic cyanobacterial blooms seriously threaten the multiple ecosystem services provided by the river, making it essential to implement cyanobacteria monitoring, and management plans to control eutrophication in the long term.  Las floraciones de cianobacterias tóxicas generan impactos negativos a nivel ambiental, económico, y en la salud humana y animal. Se realizó un análisis de datos históricos (1989-2020, n = 423) y un experimento de enriquecimiento de nutrientes para estudiar las cianobacterias del Río Negro, principal río interno del país. En base a indicadores cuantitativos (biovolumen, abundancia de células de cianobacterias y observación visual), se definieron cuatro niveles de peligrosidad de exposición a cianobacterias tóxicas. Las cianobacterias más frecuentes (Microcystis sp. y Dolichospermum sp.) son productoras potenciales de diversas toxinas, incluyendo algunas que no han sido analizadas aún en Uruguay. Se advierte un deterioro ambiental creciente desde el año 2000, pautado por el aumento de la biomasa de cianobacterias y las concentraciones de toxinas (microcistinas). Los nutrientes en el agua indican eutrofización avanzada, asociada al incremento del área agrícola de la cuenca. Los resultados experimentales demostraron el papel clave de los nutrientes y el tiempo de residencia en el favorecimiento de estos organismos. Las floraciones tóxicas de cianobacterias amenazan seriamente los múltiples servicios ecosistémicos que brinda el río, siendo indispensable la instrumentación de planes de monitoreo de cianobacterias y medidas de manejo para controlar la eutrofización a largo plazo.Blooms de cianobactérias tóxicas geram impactos ambientais e econômicos negativos, alem de danos à saúde humana e animal. Análise de dados históricos (1989-2020, n = 423) e um experimento de enriquecimento de nutrientes foram realizados para estudar as cianobactérias do Río Negro, o principal rio interno do Uruguai. Com base em indicadores quantitativos (biovolume e abundância de células cianobacterianas e observação visual) foram definidas quatro categorias de perigosidade de exposição a toxinas. As cianobactérias mais comuns (Microcystis sp. e Dolichospermum sp.) são produtoras potenciais de várias toxinas, algumas das quais nunca foram analisadas en Uruguai. Elevadas biomassas de cianobactérias  e concentrações das toxinas (microcistinas) foram encontradas desde 2000 com tendência a aumentar casos em categorias de alta perigosidade e alertando para a deterioração ambiental, a última década. Concentrações altas de nutrientes na água indicam eutrofização avançada associado com o aumento da área da bacia dedicada à agricultura. Os resultados experimentais demonstraram o papel fundamental dos nutrientes e do tempo de residencia no favorecimento de cianobactérias. A proliferação de cianobactérias tóxicas ameaçam seriamente os múltiplos serviços ecossistêmicos fornecidos pelo rio, tornando essencial a implementação de monitoramento de cianobactérias, planos de manejo e monitoreamento para controlar a eutrofização em longo prazo.

Origin of inverse Rashba-Edelstein effect detected at the Cu/Bi interface using lateral spin valves

Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).The spin transport and spin-to-charge current conversion properties of bismuth are investigated using permalloy/copper/bismuth (Py/Cu/Bi) lateral spin valve structures. The spin current is strongly absorbed at the surface of Bi, leading to ultrashort spin-diffusion lengths. A spin-to-charge current conversion is measured, which is attributed to the inverse Rashba-Edelstein effect at the Cu/Bi interface. The spin-current-induced charge current is found to change direction with increasing temperature. A theoretical analysis relates this behavior to the complex spin structure and dispersion of the surface states at the Fermi energy. The understanding of this phenomenon opens novel possibilities to exploit spin-orbit coupling to create, manipulate, and detect spin currents in two-dimensional systems.This work was supported by the European Commission under the Marie Curie Actions (Grant No. 256470-ITAMOSCINOM), the SUDOE (Grant No. TRAIN2-SOE2/P1/E-280), and the European Research Council (Grant No. 257654-SPINTROS), by the Spanish MINECO under Projects No. MAT2012-37638, No. MAT2011-13099-E, No. MAT2011-27553-C02, No. MAT2014-51982-C2-1-R, No. MAT2015-69725-REDT, and No. FIS2013-48286-C2-1-P, including FEDER funds, by the Basque Government under Project No. PI2011-1, and by the Aragon Regional Government under Project No. E26. M.I. and E.V. thank the Basque Government for Ph.D. fellowships (Grants No. BFI-2011-106 and No. BFI-2010-163).Peer Reviewe