Radio Frequency Measurements
Mostrando 1-12 de 25 artigos, teses e dissertações.
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1. IEEE 802.11b/g Practical Assessment Using a Low-Cost Quasi-Yagi Rectenna for Indoor RF Energy Harvesting
Abstract This article presents an experimental analysis of the use of signals transmitted by Wireless Local Area Networks (WLAN) based on the IEEE 802.11b/g standards for Radio Frequency Energy Harvesting (RFEH) applications in indoor environments employing a Quasi-Yagi Rectenna (QYR) topology. This analysis is a crucial point to distinguish the use of the I
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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2. Double Patch Antenna Array for Communication and Out-of-band RF Energy Harvesting
Abstract This paper presents a patch antenna array topology for Simultaneous Wireless Information and Power Transfer (SWIPT) applications. The resulting Double Patch Antenna Array (DPA) is composed of two patch antennas operating at different frequencies and fabricated on a unique substrate. One of the patches operates at the 1.8 GHz mobile communication ban
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
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3. Recurrent Algorithm for TDOA Localization in Sensor Networks
ABSTRACT: Using the mathematical apparatus of the extended Kalman Filter, the recurrent algorithm of the passive location in sensor networks - based on the Time Difference of Arrival method in case of correlated errors of measurements - is developed. The initial estimates of Radio Frequency Sources coordinates and the correlation matrix of the vector estimat
J. Aerosp. Technol. Manag.. Publicado em: 02/10/2017
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4. Evaluation of sample temperature and applied power on degradation of stearic acid in inductively coupled radio frequency plasma
Plasma cleaning is a promising technology in surface treatments, despite technological interest its use is limited because its mechanisms still are not entirely understood. This work aims to evaluate how the applied power of an inductively coupled RF discharge at 13,56 MHz, with Ar and Ar+10%O2 atmospheres, affects its capabilities to etch an organic molecul
Mat. Res.. Publicado em: 21/10/2014
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5. Channel characteristics in tunnels: FDTD simulations and measurement
This paper presents the results of measurements and simulations of the characteristics of 900 MHz band radio propagation channels in a tunnel environment. The simulations were made using the FDTD method (with companion UPML) and measurements made use of the swept frequency technique. Another method, the metaheuristic Simulated Annealing, was implemented for
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2011-06
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6. Uma plataforma para aferição remota de temperatura de bovinos da raça Brangus / A plataform for identication and measurements of remote temperature of bovine of the Brangus race
A pecuaria de precisão e uma ferramenta cada vez mais utilizada para auxiliar no correto tratamento dos produtos, na busca de alimentos cada vez mais saudaveis, no controle adequado do negocio, visando ao crescimento da produtividade e no atendimento das demandas para conquista de novos mercados, tanto interno como externo. A pecuaria de precisão introduz
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/12/2010
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7. Sistema e processo para geração, sincronização remota e comparação de sinais temporais precisos / System and process for the generation, remote synchronization and comparison of precise time signals
This thesis present new proposals for time dissemination systems, which were analyzed and implemented as complete solutions providing high resolution in radio links focusing in the requirements of the new geolocation system known as GEOLOCAL. The solutions found are useful for other applications equiring time synchronization. The work has been developed in d
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 05/07/2010
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8. Estudo das propriedades opto-eletrônicas de micro-cristais de rubi / Study of opto-electronics properties of ruby micro-crystals
Films of amorphous aluminum-nitride (AlN) were prepared by conventional radio frequency sputtering of an Al+Cr target in a plasma of pure nitrogen. The Cr-to-Al relative area determines the chromium content, which stayed in the ~ 0 3.33 at.% concentration range in the present study. Film deposition was followed by thermal annealing the samples up to 1050 ºC
Publicado em: 2010
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9. SIGNAL VARIABILITY, COHERENCE BANDWIDTH AND DELAY SPREAD ON MOBILE RADIO PROPAGATION ENVIRONMENT AT 3.5GHZ / VARIABILIDADE DO SINAL, BANDA DE COERÊNCIA E ESPALHAMENTO TEMPORAL EM AMBIENTE DE RÁDIO PROPAGAÇÃO MÓVEL EM 3,5GHZ
This work presents a study of signal variability, coherence bandwidth and delay spread of a WiMAX signal transmitted through a mobile radio propagation environment. The statistical analysis of the received signal is compared with theoretical distributions. The transmitted WiMAX signal has its physical layer based on OFDM-256 and 3.4 GHz as central frequency.
Publicado em: 2009
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10. Comparação de ferramentas para modelamento de indutores na tecnologia CMOS. / Comparison of tools for inductors model in the CMOS technology.
Two modeling tools for integrated planar square inductors and one software implementing analytical relations, were studied and analyzed, to determine which is the most appropriate, that is, the tools that will supply the closest results to experimental measurements with, lower costs, higher speed, etc. Integrated planar inductors present severe limitations i
Publicado em: 2007
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11. Project of circuits for generation of voltage reference in receiving/transmitting RF systems. / Projeto de circuitos para geração de tensão de referência em sistemas receptores/transmissores RF.
This work consists in the design of a CMOS Voltage Reference Source with a temperature coefficient inferior to 50 ppm/ºC. This voltage source should be applied in radio frequency receptor/transmitter but can be also applied in any analog system. The technology employed in the design is the CMOS 0.35 µm from the AMS (Austria Micro Systems) with four metal l
Publicado em: 2007
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12. Projeto de Transformador de Impedância de Radiofreqüência com Controle de Faixa de Passagem / Design of radio-frequency impedance transformer with bandpass control
Este trabalho apresenta um estudo preliminar e exploratório sobre os dispositivos transformadores de impedância de faixa larga em RF, freqüentemente utilizados em diversos circuitos eletrônicos. São empregados para acoplamento interestágios de cadeias amplificadoras, em circuitos híbridos, combinadores e divisores de sinais, baluns, para fins de medi�
Publicado em: 2006