Ultra Wideband
Mostrando 13-23 de 23 artigos, teses e dissertações.
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13. Coplanar waveguide-fed ultra-wideband planar antenna with WLAN-band rejection
A compact coplanar waveguide (CPW)-fed ultra-wideband (UWB) antenna is proposed with band-notched characteristic. The antenna has compact size of 29 x 31 mm². A novel wide polygon-slot is inserted on the antenna to obtain good impedance matching and wide bandwidth. A tapered radiating patch is placed inside the polygon-slot. An embedded C-slot in the radiat
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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14. On the design of nano-arm fractal antenna for UWB wireless applications
This paper presents the design of a nano-arm fractal antenna suitable for ultra wide band applications. The CPW-feed and fractal concept have been used to achieve the ultra wide bandwidth. The shape of the fractal geometry, the number of iterations and the number of nano-arms are the deciding factors for achieving wider impedance bandwidth. The experimental
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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15. On the design of UWB circular fractal antenna with notched-band characteristics using W-shape slot
This paper presents the design of notched-band antenna with CPW - feed. The notched - band has been achieved by using the W-shape slot in ground plane. The antenna has been simulated using a 3D - Electromagnetic simulator. The experimental results of proposed antenna exhibit ultra wideband characteristics from 2.0 - 15.0 GHz except the notched-band frequency
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2012-12
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16. On the design of tree-type ultra wideband fractal Antenna for DS-CDMA system
This article describes the CPW-feed ultra wideband tree type monopole fractal antenna and it’s backscattering. The prototype antenna is fabricated with optimized dimension. The experimental result of this antenna exhibits the ultra wideband characteristics from 5.0 GHz to 14.0 GHz. The experimental and simulated results are in good agreement. The effects o
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2012-06
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17. Análise de Técnicas de Detecçãoo de Sinais UWB em Ambientes PLC
O uso de banda ultra-larga (ultra wideband - UWB) vem sendo tema de pesquisa na área da comunicação sem fio há cerca de 20 anos e os bons resultados obtidos tem levado á introdução de novas tecnologias no mercado de transmissão de dados a curtas distâncias. No entanto, o uso de UWB para a transmissão de dados através da rede elétrica (power line
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/04/2011
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18. A compact wide slot antenna with dual band-notch characteristic for ultra wideband applications
A compact CPW-fed ultra-wideband antenna with dual band-notch characteristic is presented. Two notched frequency bands are obtained by embedding two U-shaped slots in the radiation patch and a rectangle slot in the ground plane. The two notched bands can be controlled by adjusting the length of the responding slots. The proposed antenna is successfully simul
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2011-06
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19. Radar UWB: antena e mecanismo para detecção de pessoas. / UWB radar: antenna and mechanism for detection of people.
A tecnologia de radar e comunicação em banda ultralarga (UWB) tem sido investigada intensamente nas últimas décadas. Esta tecnologia emprega pulsos de curta duração, que resultam em um espalhamento de energia em uma faixa ampla de frequência, fazendo com que, em transmissão de dados, o sinal apareça como ruído branco, dificultando a sua intercepta�
Publicado em: 2011
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20. Desenvolvimento de monopolos quase-espirais para aplicações em sistemas UWB
Este trabalho consiste na análise de uma estrutura de antena de microfita projetada para aplicação em sistemas de banda ultra larga (ultra wideband UWB). Trata-se de um estudo prospectivo e analítico onde são experimentadas as modificações na geometria da antena, observando-se sua adequação aos objetivos propostos. Sabe-se que a antena UWB deve oper
Publicado em: 2009
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21. Development of wideband bandpass filter with zeros transmition for ultrawideband communication systems / Desenvolvimento de filtro passa-faixa banda larga com zeros de transmissão para sistemas de comunicação Ultra-Wideband (UWB)
The quick development of wireless communications has introduced new requirements for communications systems being the use of more selective microwave filters. Different filter structures have been developed for applications in UWB systems (Ultra WideBand). It is presented in [1, 2] the highly selective microstrip bandpass filter. In this work, a bandpass fil
Publicado em: 2007
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22. MEASUREMENT AND ANALYZE OF UWB INDOOR CHANNEL TEMPORAL DISPERSION IN SEVERAL ENVIRONMENT TYPES / MEDIDAS E ANÁLISE DA DISPERSÃO TEMPORAL DO CANAL DE PROPAGAÇÃO UWB INDOOR EM VÁRIOS TIPOS DE AMBIENTES
This work presents an analysis of the ultra wideband (UWB) channel temporal dispersion characteristics evaluated from the frequency sounding technique over a bandwidth of 850MHz at seven different indoor environment. In each environment, the channel temporal dispersions parameters were assessed in terms of mean delay, delay spread and coherence bandwidth. An
Publicado em: 2005
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23. Design of distributed microwave oscillators with reverse feedback. / Projeto de osciladores de microondas distribuídos com realimentação reversa.
In this dissertation, a design methodology applied to microwave reverse feedback distributed voltage controlled oscillators - DVCO - is proposed. This circuit constitutes a new class of oscillators, obtained from reverse feeding back of the distributed amplifier. The main advantage of this topology is its capacity to achieve ultra-wideband frequency tuning.
Publicado em: 2005