Subject: [NEXTEL-1] Researchers Overcome Barrier To Shrinking Wireless Devices

From: [email-masked]
Date: Wed, 04 Aug 2004 07:12:37 -0400

Researchers Overcome Barrier To Shrinking Wireless Devices

Ann Arbor MI (SPX)

 July 22, 2004

James Bond-style technologies such as cell phones the size of earpieces
and
invisible sensors sprinkled about to detect toxins are closer to
reality.
University of Michigan researchers have figured out how to build
wireless
systems even smaller while still retaining range and power efficiency.
One obstacle to further shrink small wireless devices has been trying to
fit all the components onto one chip but U-M researchers have built a
tiny
silicon-compatible antenna and frequency resonator that will do just
that.

The antenna and resonator are two of the most problematic off-chip
components in wireless systems. The two components require large amounts
of
space off the chip (think of a cell phone antenna extending outward)
thus
limiting how small a device can be built.

Until now, small antennas weren't power efficient and resonators were
not
accurate, said Kamal Sarabandi, director of the radiation laboratory
department in electrical engineering and computer science (EECS). His
research group developed the antenna.

The technology is being developed for use in environmental sensors, but
could be applied to cell phones, laptops and other wireless devices,
said
Michael Flynn, head of the wireless interface group.

"We could have cell phones almost the size of an earpiece," Flynn said.
"You could have sensor nodes that are almost invisible, you could just
sprinkle them around."

Rather than using a traditional wire antenna, researchers built a slot
antenna. In a slot antenna, instead of the metal wire, imagine covering
an
entire plane with metal, leaving only a slot or groove in the metal
bare.

Wire surrounds the groove so it's much more effective at radiating
electromagnetic waves in a small antenna, Sarabandi said. Because of the
antenna's shape, the wireless system does not need a network to match
the
antenna's frequency to the rest of the electronic device.

Sarabandi's group has been talking with Intel about a possible
collaboration. Intel is interested in using the technology in laptop
computers, Sarabandi said.

The second component U-M scientists replaced is the quartz frequency
resonator, which allows a wireless device to focus on a specific signal
and
ignore others. The work was done by EECS associate professor Clark
Nguyen's
group.

Instead of quartz, U-M scientists used MEMS-based technology to build
the
resonator so it can be fitted onto the chip. It functions similarly to
how
the rim of a wine glass thrums when flicked by a finger. The wine-glass
rim
design helps retain the purity of the signal.

http://www.spacedaily.com/news/nanotech-04zzd.html

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