ARLA/CLUSTER: Antenas em metamateriais*.

Carlos Mourato radiofarol
Segunda-Feira, 31 de Agosto de 2009 - 14:31:12 WEST

Isto cheira-me a outra historia como a da "antena enterrada"

2009/8/31 João Gonçalves Costa <joao.a.costa>

> 'Invisibility cloak' antennas
> The materials used to make real-life invisibility cloaks could also make
> antennas smaller.
> *New Scientist* reports that "an international team of physicists has now
> created metamaterials that can be tuned to a range of different frequencies
> as required. A cellphone antenna fashioned from the new material could be
> tuned to work very efficiently across a small frequency range, but retuned
> to a different band for roaming."
> "Because metamaterials can manipulate electromagnetic waves to a greater
> degree than normal materials – and even bend light "backwards" – a small
> metamaterial antenna is as effective as a much larger standard antenna at
> transmitting or receiving waves."
> "But a narrowband metamaterial antenna has its drawbacks – it's rare that
> engineers require an antenna tuned to just one frequency, for instance,
> different countries have allocated different frequency bands to their
> cellphone networks. A tunable metamaterial antenna could allow a wireless
> gadget to work "outstandingly well" at the frequencies used in one country,
> but also carry the option of retuning for use abroad."
> Read the New Scientist article - *'Invisibility cloak' antennas could
> shrink cellphones* - at
> cloak-antennas-could-shrink-cellphones.html<>
> Active invisibility cloaks could work at many wavelengths
> *Um *Metamaterial* é um material produzido artificialmente e que é dotado
> de propriedades que não existem na natureza.
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Best 73 from: regards from: CT4RK Carlos Mourato - Sines - Portugal

Save the Radio Spectrum! Eliminate Broadband over Power Line. Salve o
espectro electromagnético!. Não use a rede electrica para transmitir dados.
Os "homeplugs power line" e a tecnologia "power line" causa fortes
interferencias noutro serviços sem voce se aperceber. Diga não à tecnologia
power line. Proteja o ambiente
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