Rain Attenuation
Mostrando 1-12 de 24 artigos, teses e dissertações.
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1. Analysis of Wet Antenna Losses on 11.843 GHz Slant Path in Nigeria and Comparison with Some Tropical Climates
Abstract The amount of water deposits on the receiving dish antenna can cause additional losses and consequently contaminate the actual slant-path attenuation. Only a few research works have been reported in the literature on the measurement of wet antenna attenuation (WAA) and the technique(s) of extracting the losses from the total attenuation in tropical
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Assessment of Total Attenuation and Adaptive Scheme for Quality of Service Enhancement in Tropical Weather for Satellite Networks and 5G Applications in Nigeria
Abstract The dynamic weather condition is a major concern for optimum channel utilization in recent times, especially at higher frequencies with larger bandwidth for 5G applications. Over the years, rain-induced attenuation among the hydrometeors has been linked as the major cause of signal impairment especially at the frequency, f ≥ 10 GHz. However, when
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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3. Malting of preharvest sprouted wheat
RESUMO Germinação pré-colheita é um importante problema da cultura do trigo, sendo necessário encontrar alternativas para uso desses grãos porque eles são rejeitados pelos moinhos. No campo, sob determinadas condições climáticas, os grãos são estimulados a germinar, a atividade metabólica aumenta e as enzimas hidrolíticas alteram proteínas e c
Rev. Ciênc. Agron.. Publicado em: 04/11/2019
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4. Statistical Evaluation of Measured Rain Attenuation in Tropical Climate and Comparison with Prediction Models
Abstract Substantial modifications have been made to the expressions for calculating distance factor and extrapolation techniques in the latest ITU-R P.530-14. However, its performance has not been rigorously evaluated in the tropical and equatorial climates. In this article, the new ITU-R method and three prediction models are validated using measurement da
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-06
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5. Modified rain attenuation prediction method considering the effect of wind direction
The method currently recommended by the ITU-R for the prediction of rain attenuation in terrestrial line-of sight links considers an equivalent path length over which the rain intensity is assumed to be constant. In other methods, the spatial and temporal variations of the rainfall rate along the path are characterized by an effective rainfall rate that is d
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-12
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6. Extension of the Misme and Fimbel model for the estimation of the cumulative distribution function of the differential rain attenuation between two converging terrestrial links
A distribution-free model is presented for the cumulative distribution function of the differential rain attenuation between two co-channel converging terrestrial links operating at frequencies above 10 GHz. This is accomplished through an extension of the Misme and Fimbel model, which determines the cumulative distribution of the rain attenuation on an isol
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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7. Sistema para medição da atenuação devido à chuva em enlaces de satélites na banda Ku
Dentre as degradações sofridas por um sinal de RF a partir de 10GHz num enlace via satélite, a atenuação devido à chuva, é a que provoca o efeito mais significativo e prejudicial. Essa atenuação impõe ao projeto de um sistema de comunicação a reserva de uma margem, que acarreta em aumentos de potencia, uso de antenas maiores ou de técnicas compl
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/09/2012
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8. Statistical modeling of rain attenuation in tropical terrestrial links
This paper presents a statistical modeling of rain attenuation in terrestrial links located in a tropical region using different types of distribution. Each distribution is tested against long-term statistics of data collected during up to two years of experimental measurements in links operating at 15 GHz. Statistics obtained from each distribution are test
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2012-12
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9. Unified method for the prediction of rain attenuation in satellite and terrestrial links
In this paper, a semi-empirical method for the prediction of rain attenuation in slant paths and terrestrial links is proposed. The method uses the same simplified model of equivalent rain cell that is the basis for the ITU-R rain attenuation prediction methods but, additionally, the concept of an effective rain rate is introduced. This allows the use of the
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2012-06
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10. Terrestrial rain attenuation time series synthesizers for tropical regions
The aim of this paper is to present and validate rain attenuation time series synthesizers relying on the Maseng-Bakken principle for terrestrial links in tropical areas. Data obtained in experimental measurements at four links operating at 15 GHz in São Paulo, Brazil, are used to parameterize the synthesizers. Two models are tested with respect to long-ter
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2011-06
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11. RAIN ATTENUATION TIME SERIES SYNTHESIZERS FOR TERRESTRIAL LINKS / SINTETIZAÇÃO DE SÉRIES TEMPORAIS DE ATENUAÇÃO POR CHUVAS EM ENLACES TERRESTRES
A atenuação por chuva é a causa principal de indisponibilidade em enlaces terrestres de rádio operando em frequências acima de 10 GHz. Devido às condições adversas de propagação, técnicas de mitigação de desvanecimentos são necessárias. Para desenvolver e otimizar estas técnicas, é preciso conhecer a distribuição cumulativa de atenuação
Publicado em: 2010
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12. Desenvolvimento de procedimentos analíticos limpos e com alta sensibilidade para a determinação de espécies de interesse ambiental / Development of clean analytical procedures with high sensitivity for determination of species of environmental interest
Clean analytical procedures with high sensitivity for the determination of species of environmental interest (carbaryl, sulphate and chlorine) were developed. Flow systems with solenoid micropumps were coupled to long optical pathlength spectrophotometry or cloud point extraction procedures, aiming the concentration of species for determination without emplo
Publicado em: 2009