Implementação de conversor de polarização linear-circular para antenas de microfita usando metasuperfícies

This work aims to propose a new model of metasurface with simplified basic cell, able to convert linearly polarized signals generated by planar antenna array in circularly polarized signals, for the ISM frequency band (2.45 GHz), with good bandwidth of return loss and axial ratio. To study the behavior of the proposed structure, the metasurface is coupled to three different structures. First, initial tests are made with the metasurface coupled to a microstrip antenna in its simple configuration. Then the metasurface is coupled to an array with two elements of patch type. And later it is coupled to an optimized array, that uses a stub in its main feed, to get a better impedance matching. The structures are analyzed numerically through Ansoft HFSS™, and to validate these results, the structures are characterized experimentally. The characteristics of transmissions simulated and measures are presented. A good agreement between simulated and measured results was obtained. The structure proposed here has the advantage of meeting the desired characteristics, with a simple geometry to be built using a low-cost substrate (FR-4).

Sistemas de cálculo, análise e operação virtual: interferências de campos elétricos e magnéticos produzidas por estações radio base de acesso múltiplo por divisão de código em banda larga - WCDMA

In this work it was developed mathematical resolutions taking as parameter maximum intensity values for the interference analysis of electric and magnetic fields and was given two virtual computer system that supports families of CDMA and WCDMA technologies. The first family were developed computational resources to solve electric and magnetic field calculations and power densities in Radio Base stations , with the use of CDMA technology in the 800 MHz band , taking into account the permissible values referenced by the Commission International Protection on non-Ionizing Radiation . The first family is divided into two segments of calculation carried out in virtual operation. In the first segment to compute the interference field radiated by the base station with input information such as radio channel power; Gain antenna; Radio channel number; Operating frequency; Losses in the cable; Attenuation of direction; Minimum Distance; Reflections. Said computing system allows to quickly and without the need of implementing instruments for measurements, meet the following calculated values: Effective Radiated Power; Sector Power Density; Electric field in the sector; Magnetic field in the sector; Magnetic flux density; point of maximum permissible exposure of electric field and power density. The results are shown in charts for clarity of view of power density in the industry, as well as the coverage area definition. The computer module also includes folders specifications antennas, cables and towers used in cellular telephony, the following manufacturers: RFS World, Andrew, Karthein and BRASILSAT. Many are presented "links" network access "Internet" to supplement the cable specifications, antennas, etc. . In the second segment of the first family work with more variables , seeking to perform calculations quickly and safely assisting in obtaining results of radio signal loss produced by ERB . This module displays screens representing propagation systems denominated "A" and "B". By propagating "A" are obtained radio signal attenuation calculations in areas of urban models , dense urban , suburban , and rural open . In reflection calculations are present the reflection coefficients , the standing wave ratio , return loss , the reflected power ratio , as well as the loss of the signal by mismatch impedance. With the spread " B" seek radio signal losses in the survey line and not targeted , the effective area , the power density , the received power , the coverage radius , the conversion levels and the gain conversion systems radiant . The second family of virtual computing system consists of 7 modules of which 5 are geared towards the design of WCDMA and 2 technology for calculation of telephone traffic serving CDMA and WCDMA . It includes a portfolio of radiant systems used on the site. In the virtual operation of the module 1 is compute-: distance frequency reuse, channel capacity with noise and without noise, Doppler frequency, modulation rate and channel efficiency; Module 2 includes computes the cell area, thermal noise, noise power (dB), noise figure, signal to noise ratio, bit of power (dBm); with the module 3 reaches the calculation: breakpoint, processing gain (dB) loss in the space of BTS, noise power (w), chip period and frequency reuse factor. Module 4 scales effective radiated power, sectorization gain, voice activity and load effect. The module 5 performs the calculation processing gain (Hz / bps) bit time, bit energy (Ws). Module 6 deals with the telephone traffic and scales 1: traffic volume, occupancy intensity, average time of occupancy, traffic intensity, calls completed, congestion. Module 7 deals with two telephone traffic and allows calculating call completion and not completed in HMM. Tests were performed on the mobile network performance field for the calculation of data relating to: CINP , CPI , RSRP , RSRQ , EARFCN , Drop Call , Block Call , Pilot , Data Bler , RSCP , Short Call, Long Call and Data Call ; ECIO - Short Call and Long Call , Data Call Troughput . As survey were conducted surveys of electric and magnetic field in an ERB , trying to observe the degree of exposure to non-ionizing radiation they are exposed to the general public and occupational element. The results were compared to permissible values for health endorsed by the ICNIRP and the CENELEC .

Sistema de rádio comunicações para UAV

Os veículos aéreos não tripulados, mais conhecidos por drones, têm tomado atualmente uma posição importante na sociedade. Para além da sua importância no meio militar, têm sido cada vez mais utilizados para meios comerciais uma vez que o seu custo é relativamente baixo e podem ser utilizados para inúmeras aplicações. Devido à sua importância em missões de salvamento, reconhecimento de terreno e até mesmo de ataque, é fundamental uma boa comunicação entre a aeronave e a estação terrestre. Sendo a antena um dos principais elementos do sistema de comunicação, esta dissertação centrou-se no desenvolvimento de uma agregado de antenas a operar à frequência de 2.45GHz. Pretende-se que este agregado apresente polarização circular direita bem como um ganho e largura de banda elevados. Com o objetivo de se obter uma comunicação mais eficiente entre a aeronave e a estação terrestre, o agregado permitirá o redirecionamento do feixe principal do diagrama de radiação. Para tal, serão analisadas três abordagens distintas recorrendo a linhas de atraso e switches, permitindo que seja efetuado beamforming.

Estádios larvais e ocorrência sazonal de imaturos de Psaroniocompsa incrustata (Lutz,1910)(Diptera:Smimuliidae) no Rio Pium, município de Nísia Floesta, RN

The larval instars, seasonal occurrence and environmental factors influence on Psaroniocompsa incrustata (Lutz, 1910) (Diptera: Simuliidae) immature were studied according to its physical and chemical aspects of breeding water. Four collects were made at vegetal substrate from margin, middle and floating on the Pium river, city of Nísia Floresta, state of Rio Grande do Norte, Brazil at dry and wet season. Some of larval characters were used to determinate the larval instars number like lateral length of cephalic capsulae, antennae and the distance among cephalic apodema, as well as pH, water temperature, width, depth, stream velocity, discharge and pluviometric precipitation were used for physical factors. Seven larval instars were determined for this P. incrustata community being the lateral length of cephalic capsulae as the best structure with this meaning propose. The seasonality immature abundance of this species were found in dry season and a positive correlation with pH, stream velocity and precipitation

El uso de la documentación audiovisual en los programas informativos diarios de televisión

[SPA] El objetivo de la investigación es conocer cual es la aportación cuantitativa y cualitativa de la documentación audiovisual en la información que ofrece diariamente la televisión. El marco temporal de la investigación de campo se sitúa en los años 1993 y 1994, en un marco geográfico constituido por los canales que emiten en el estado español. El estudio parte de una aproximación teórica a la documentación periodística, a la documentación audiovisual y a los estudios sobre la comunicación de masas, y lleva a cabo una investigación de campo en tres áreas: 1) Análisis de programas informativos diarios de seis cadenas de televisión (ETB, TVE, Canal Sur, TV3, Antena 3 y Canal+), a través de tres muestras independientes. 2) Análisis de las peticiones de documentación audiovisual realizadas desde las redacciones de programas informativos a los servicios de documentación. 3) Estudio de las funciones, tareas, estructura y organización de los servicios de documentación de televisión, basado en encuestas, visitas y entrevistas. En anexo se ofrece el análisis detallado de 620 noticias, así como la información de los centros de documentación. La investigación concluye afirmando que la documentación audiovisual es uno de los elementos constitutivos de la información de actualidad, tanto por su presencia cuantitativa (más de un 40% de las noticias emitidas la emplean), como por su aportación cualitativa y su utilización generalizada en todas las secciones informativas. Las conclusiones señalan que la importancia de las noticias incide positivamente en el empleo de documentación audiovisual, sintetizan las funciones de esta documentación y las características específicas de su uso. Confirman el carácter de retroalimentación de la documentación informativa en televisión. Señalan un empleo de esta documentación como documentación puramente visual. Y afirman que la documentación audiovisual, además de contribuir en la producción, coadyuva a la calidad de los programas informativos, en la medida en que facilita la tarea de ofrecer una información más completa y contextualizada.

A utilização das redes sociais pela Guarda Nacional Republicana no âmbito da prevenção rodoviária

Sabendo que grande parte do combate ao flagelo que é a sinistralidade rodoviária, passa pela prevenção e que as redes sociais são ferramentas cada vez mais utilizadas no quotidiano, pela sociedade, tendo passado a ser um veículo cada vez mais utilizado para comunicar com as pessoas, surge a presente investigação intitulada: “A utilização das redes sociais pela Guarda Nacional Republicana no âmbito da Prevenção Rodoviária”. O objetivo geral do presente Trabalho de Investigação Aplicada, é determinar o contributo da utilização das redes sociais na divulgação da Prevenção Rodoviária, por parte da Guarda Nacional Republicana. Nesta investigação adotou-se o método hipotético-dedutivo tendo-se a presente investigação desenvolvido em três fases: exploratória, analítica e conclusiva. A primeira fase consiste num levantamento bibliográfico e documental. A segunda fase consiste em análise documental, na recolha e tratamento de dados resultantes da realização de entrevistas, e na respetiva apresentação, análise e discussão dos mesmos, respondendo-se ainda às hipóteses de investigação, lançadas no início da investigação. Na terceira fase, responde-se às perguntas derivadas e à pergunta de partida, frisando ainda algumas dificuldades sentidas durante a realização desta investigação. Assim, conclui-se que ao aderir às redes sociais, a instituição passou a ser um ator ativo e autónomo no processo de comunicação, não necessitando constantemente da comunicação social para passar determinada mensagem. A instituição pode e deve complementar e tomar a iniciativa, em situações em que a comunicação social dê uma importância redutora a certas campanhas, relevando o papel da utilização das redes sociais, sendo possível atingir números bastante consideráveis de pessoas. Além disso, passou a ser possível pôr em prática campanhas e ações de autoria própria, elevando assim o nome da Guarda, tornando-a num produto “apetecível” para a comunicação social, fazendo com que venham ter com a instituição e estejam interessados em que esta faça parte do seu tempo de antena, especialmente da televisão.

Um modelo matemático baseado em wavelets para análise do método térmico de recuperação de óleo pesado aplicando irradiação eletromagnética

This work proposes a model to investigate the use of a cylindrical antenna used in the thermal method of recovering through electromagnetic radiation of high-viscosity oil. The antenna has a simple geometry, adapted dipole type, and it can be modelled by using Maxwell s equation. The wavelet transforms are used as basis functions and applied in conjunction with the method of moments to obtain the current distribution in the antenna. The electric field, power and temperature distribution are carefully calculated for the analysis of the antenna as electromagnetic heating. The energy performance is analyzed based on thermo-fluid dynamic simulations at field scale, and through the adaptation in the Steam Thermal and Advanced Processes Reservoir Simulator (STARS) by Computer Modelling Group (CMG). The model proposed and the numerical results obtained are stable and presented good agreement with the results reported in the specialized literature

Estádios larvais e ocorrência sazonal de imaturos de Psaroniocompsa incrustata (Lutz,1910)(Diptera:Smimuliidae) no Rio Pium, município de Nísia Floesta, RN

The larval instars, seasonal occurrence and environmental factors influence on Psaroniocompsa incrustata (Lutz, 1910) (Diptera: Simuliidae) immature were studied according to its physical and chemical aspects of breeding water. Four collects were made at vegetal substrate from margin, middle and floating on the Pium river, city of Nísia Floresta, state of Rio Grande do Norte, Brazil at dry and wet season. Some of larval characters were used to determinate the larval instars number like lateral length of cephalic capsulae, antennae and the distance among cephalic apodema, as well as pH, water temperature, width, depth, stream velocity, discharge and pluviometric precipitation were used for physical factors. Seven larval instars were determined for this P. incrustata community being the lateral length of cephalic capsulae as the best structure with this meaning propose. The seasonality immature abundance of this species were found in dry season and a positive correlation with pH, stream velocity and precipitation