Design of a Rotman lens operating in the full K/Ka band using ridge waveguide technology

Several services associated with satellite on the move and 5G applications are populating the K and Ka frequency bands. Beam forming networks are crucial components for achieving the necessary beam flexibility and agility of these systems. The Rotman lens is being widely investigate as a cost-effective solution for overcoming the main limitations of other types of beam forming networks, namely bandwidth, complexity, and size. One of the main design challenges is obtaining broadband transitions for the array and beam ports. In this work, we used a standard K/Ka double ridge (WRD180) for interfacing with the Rotman Lens. The main motivation for this choice is the wide bandwidth, compatible with the K/Ka satcom frequency bands, and the use of air/vacuum propagation medium in the parallel plate waveguide section to avoid dielectric losses associated with microstrip implementations. We present a design capable of fully exploiting the ridge waveguide bandwidth with wide beam scanning, outperforming previous works. The presented design consists of a 13×7 Rotman Lens with a scanning range of ±50 degrees operating between 16 and 40 GHz, validated through full-wave simulations.info:eu-repo/semantics/acceptedVersio

Environmental education in urban centers: a word about an experience in public education in Curitiba, Paraná State

Este relato presenta una experiencia de educación ambiental realizada en el 2006 por el grupo PET-Geología de la Universidade Federal do Paraná. Para dicha experiencia fue elegida una clase de sexto año  de enseñanza fundamental del Colegio Estatal Hildebrando de Araújo, de Curitiba (Paraná-Brasil). En los trabajos se utilizaron actividades lúdicas y material audiovisual para interrelacionarse mejor con los alumnos, ofreciéndoles actividades en clase en una forma diferente a aquella enseñanza practicada en la escuela. Cuestiones del cotidiano urbano fueron integradas al contenido científico presentado. La asimilación de los conceptos por los estudiantes fue grande y los resultados positivos. Las principales dificultades verificadas durante la experiencia fueron la falta de noción de los alumnos sobre su espacio geográfico, el poco conocimiento sobre la importancia del uso racional del ambiente y la necesidad de refuerzo en la formación continuada de algunos de los profesores en relación a los temas propuestos.This paper describes an experience in the environmental education field, that happened in 2006, concerning the PET-Geologia group from the Federal University of Paraná. In that occasion, a sixth grade class was chosen from the Hildebrando de Araújo School, of Curitiba. The project’s development was based on ludic activities and audiovisual resources, in order to better interact with the students and offer a non-usual approach in teaching. Technical-scientific content was integrated with urban life issues and presented to the class. All the subjects were well absorbed by the students. The main difficulties in the project were poor notion of the students about geographic space, as well as their lack of knowledge about the importance of the environmental consciousness in using nature’s resources, and the necessity of a reinforcement of a continuous training of teachers on the related subjects.Este relato apresenta experiência de educação ambiental, realizada em 2006 pelo grupo PET-Geologia da Universidade Federal do Paraná (UFPR). Na ocasião foi escolhida uma turma de sexta série do ensino fundamental do Colégio Estadual Hildebrando de Araújo, de Curitiba. O desenvolvimento dos trabalhos apoiou-se em atividades lúdicas e material audiovisual para melhor interação com os alunos, de modo a oferecer atividades em sala de aula, num formato não usual no ensino do colégio. Questões do cotidiano urbano foram integradas ao conteúdo técnico-científico apresentado à turma. A assimilação dos conceitos pelos estudantes foi grande e os resultados positivos. As principais dificuldades verificadas durante a experiência foram: falta de noção dos alunos sobre o que é espaço geográfico, seu pouco conhecimento sobre a importância do uso racional do ambiente e necessidade de reforço na formação continuada de alguns professores em relação aos temas propostos