Radio Frequency
Mostrando 1-12 de 191 artigos, teses e dissertações.
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1. Broadband Antennas Based on the Double Moebius Strip
Abstract The family of new antenna designs based on the double Moebius strip principle is proposed in this article. Three possible options of the power supply port location had been reviewed in this respect: the cut external strip with the signal port located directly in the cut area is used; the continuous rings without discontinuities are applied, with the
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Single Port Multimode Reconfigurable UWB-NB Antenna for Cognitive Radio Applications
Abstract In this paper, a compact, single port, multimode reconfigurable UWB-NB antenna with a novel feeding network is presented. The proposed antenna consists of a pentagonal-shaped monopole radiator, a beveled-shaped partial defected ground plane with a rectangular slot, and a reconfigurable bypass feeding network. The antenna realizes a wideband frequenc
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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3. DRYING CHARACTERISTICS AND QUALITY ANALYSIS OF HOT AIR-ASSISTED RADIO FREQUENCY AND HOT-AIR DRYING OF JUJUBE ( Zizyphus jujube Miller cv. Jinsixiaozao )
ABSTRACT Radio frequency (RF) drying is a rapid dehydration technique that reduces water activity and extends the shelf life of agricultural products. In this study, the drying characteristics of jujube during HARF and hot air (HA) were investigated, and quality analyses, such as color, vitamin C (VC) and total flavonoid content (TFC), of jujube were perform
Engenharia Agrícola. Publicado em: 2022
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4. 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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5. Passively Q-Switched Pulses Generation from Erbium-Doped Fiber Laser Using Lutetium Oxide as Saturable Absorber
Abstract In this paper, a configuration of a passive Q-switched Erbium-doped fiber laser (EDFL) using a Lutetium Oxide (Lu2O3) thin film as a saturable absorber (SA) is experimentally implemented to generate high pulse energy with a high signal to noise ratio. A stable Q-switched pulse train is initiated at the input pump power of 30.442mW, and a maximum pul
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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6. Left Atrial Appendage Thrombosis and Persistent Atrial Fibrillation: combined Treatment with a Totally Thoracoscopic Approach
Abstract Minimally invasive surgical ablation is generally contraindicated in patients with atrial fibrillation and thrombosis of the left atrial appendage. We have treated three of these patients using an innovative technique based on a bilateral video-thoracoscopic approach, performing a continuous encircling lesion at the pulmonary veins outflow with radi
Braz. J. Cardiovasc. Surg.. Publicado em: 2020-12
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7. 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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8. Electromagnetic Energy Harvesting Using a Glass Window
Abstract In this work, a new constructive and conceptual model for rectenna, using glass as dielectric substrate, was proposed. This research aims to produce a window for building facades that can harvest the electromagnetic energy available in the environment. For this proposal, a slotted patch antenna was designed with two main objectives: to have a low va
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-03
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9. Verification of atmospheric plasma irradiation as an alternative control method for Tribolium castaneum (Herbst)
Resumo Plasma de radiofrequência, plasma de RF, tem sido empregado em diversas aplicações industriais. Experimentos de laboratório foram conduzidos para determinar o potencial de plasma de RF no controle de Tribolium castaneum (Herbst). Foram examinados nesse estudo três variáveis de tratamento: (1) plasma de hélio ou argônio; (2) dois níveis de pot
Braz. J. Biol.. Publicado em: 21/10/2019
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10. RFID na edificação: proposta de modelo de sistema para organização das informações de manutenção
Resumo A indústria da construção civil é vista como uma indústria baseada no conhecimento. Ao longo do processo de projeto de uma edificação várias informações são geradas e compõem uma série de documentos que, após a conclusão da obra, devem ser entregues aos proprietários e gestores das edificações para a devida manutenção do imóvel. E
Ambient. constr.. Publicado em: 03/10/2019
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11. IoT-based measurement system for classifying cow behavior from tri-axial accelerometer
RESUMO: Um sistema de monitoramento de comportamento de vacas baseado na Internet das Coisas (IoT) foi projetado e implementado através do uso de acelerômetro tri-axial, Microcontrolador MSP430, módulo de rádio, frequência sem fio (RF), e um portátil. O sistema implementado mediu o comportamento do movimento da vaca e transmitiu dados de aceleração
Cienc. Rural. Publicado em: 13/06/2019
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12. Al-doping and Properties of AZO Thin Films Grown at Room Temperature: Sputtering Pressure Effect
Aluminum zinc oxide (AZO) thin films were synthesized on glass substrates by radio frequency (rf) magnetron sputtering from a metallic Zn-Al (5 at. %) target at room temperature. The morphological, structural, electrical and optical properties of the films were studied as a function of the sputtering pressure, which was varied from 0.1 to 6.7 Pa. X-ray diffr
Mat. Res.. Publicado em: 09/05/2019