Application of Huygens’ Metasurfaces to the Arbitrary Design of a Leaky-Wave Antenna

Leaky-wave antennas are guiding structures that leak power along their length. Their radiation is mainly characterized by the propagation constant (leakage factor and phase constant) of the traveling wave. In this contribution, a leakywave antenna based on parallel-plate waveguide is proposed. Arbitrary control of the leakage factor and the phase constant is achieved by replacing the top plate by an omega-type bianisotropic Huygens’ metasurface, which implements the desired field transformation. The theoretical derivation and design methodology are briefly described. Several designs with different pointing angles (phase constants) and leakage rates have been carried out. Electromagnetic simulation results validate the theoretical derivation, highlight the capabilities of the structure and confirm the flexibility in the design parameters.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Leaky-Wave antennas with arbitrary radiation based on bianisotropic Huygens’ metasurfaces

In this contribution, we present the application of Huygens’ metasurfaces (HMS) to the arbitrary design of leaky-wave antennas (LWAs). These metasurfaces have demonstrated their capabiity to tailor the electromagnetic waves at will. We use them to design LWAs consisting on a parallel-plate waveguide in which the top cover is replaced by a HMS, which implements the desired field transformation. By introducing bianisotropy of the omega type into the metasurface, we have the required degrees of freedom to achieve arbitrary control of the LWA radiation parameters: leakage factor and pointing angle (phase constant). The theoretical derivation of the concept and the design methodology will be described. Moreover, the flexibility in the design will be highlighted with results of two examples of broadside radiation with different directivities.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 706334

New record of Abelisauroid Theropods from the Bauru group (upper cretaceous), São Paulo State, Brazil

Isolated bones of abelisauroid theropods from the Bauru Group (Late Cretaceous, Brazil), are described. They correspond to three individuals represented by fused ischia and part of the ilium, a partial axis, and a right fi bula, respectively. The fossils come from different sites in the municipalities of Ibirá (axis and fi bula) and Monte Alto (ilium and ischia), São Paulo State, from Maastrichtian beds of the São José do Rio Preto and the Marília formations (Bauru Group), respectively. The specimens provide new information on abelisauroids which are still poorly known in the Brazilian fossil record, and on the distribution of this diverse group of theropod dinosaurs in South America. These discoveries indicate that abelisauroids were the most common large predatory dinosaurs in the outcrops where they come from.Ossos isolados de terópodes abelissauroides do Grupo Bauru (Cretáceo Superior), Brasil, são descritos. O material consiste de restos de três indivíduos, um representado pelos ísquios fusionados e parte do ílio, outro por um fragmento de áxis e outro por uma fíbula direita. Os fósseis, oriundos dos municípios de Ibirá (áxis e fíbula) e Monte Alto (ílio e ísquios fusionados), Estado São Paulo, foram descobertos em depósitos maastrichtianos das formações São José do Rio Preto e Marília (Grupo Bauru), respectivamente. Os espécimes fornecem novas informações sobre abelissauroides, ainda são pouco conhecidos no registro fóssil brasileiro, e sobre a distribuição deste grupo diverso de dinossauros terópodes na América do Sul. Estas descobertas indicam que os abelissauroides foram os grandes dinossauros predadores mais comuns nos afl oramentos de onde eles provêm.Fil: Méndez, Ariel Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Novas, Fernando Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Iori, Fabiano V.. Universidade Federal do Rio de Janeiro; Brasi