Antennas that use plasma to focus beams of radio waves could bring us superfast wireless networks
BEFORE you leave for work in the morning, your smartphone downloads the latest episode of a television series. Your drive to work is easy in spite of fog, thanks to in-car radar and the intelligent transport software that automatically guides you around traffic jams, allowing you to arrive in time for a presentation in which high-definition video is streamed flawlessly to your tablet computer in real time.
This vision of the future may not be far off, thanks to a new type of antenna that makes use of plasma consisting of only electrons. It could revolutionise high-speed wireless communications, miniature radar and even energy weapons.
Existing directional antennas that transmit high-frequency radio waves require expensive materials or precise manufacturing. But the new antenna, called Plasma Silicon Antenna, or PSiAN, relies on existing low-cost manufacturing techniques developed for silicon chips. It has been developed by Plasma Antennas of Winchester, UK.
PSiAN consists of thousands of diodes on a silicon chip. When activated, each diode generates a cloud of electrons - the plasma - about 0.1 millimetres across. At a high enough electron density, each cloud reflects high-frequency radio waves like a mirror. By selectively activating diodes, the shape of the reflecting area can be changed to focus and steer a beam of radio waves. This "beam-forming" capability makes the antennas crucial to ultrafast wireless applications, because they can focus a stream of high-frequency radio waves that would quickly dissipate using normal antennas.
"Beam-forming antennas are the key for enabling next-generation, high-data-rate indoor wireless applications," says Anmol Sheth, at Intel Labs in Seattle. "Without beam-forming antennas it would be difficult to scale to the levels of density of wireless devices we expect to have in future homes."
There are two types of plasma antenna: semiconductor or solid-state antennas, such as PSiAN, and gas antennas. Both could fit the bill, but solid-state antennas are favoured as they are more compact and have no moving parts.
Read more at New Scientist
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