TECH KNOWLEDGEY
EVENTS, ADVANCES, AND NEWS
2008
■ BY JEFF ECKERT
ADVANCED TECHNOLOGY
ANTENNA ACHIEVES
NEAR-PERFECT
PERFORMANCE
PHOTO COUR TES Y OF VIRGINIA TECH.
■ The compact ultrawideband
antenna sans its radome.
Virginia Tech ( www.vt.edu)
researchers have come up with
a compact ultrawideband antenna
(CUA) that has potential applications
in medical, military, automotive, and
home entertainment devices. Most
notably, it is said to operate at nearly
the theoretical limit on antenna size
and performance. According to the
official description, the CUA “has at
least 10:1 instantaneous bandwidth
and nearly constant omnidirectional
radiation patterns, high efficiency
(>95%), and 5 dBi realized gain over
the entire band. In addition, the
antenna provides a short pulse
radiation characteristic. The electrical
size of the CUA is approximately
1/10 wavelength at the lower bound
of the band, which is two times
smaller than conventional ultrawideband antennas.”
Ultrawideband antennas are
designed for a wide range of low
energy, short-range transmissions,
so this one could prove useful not
only for data transmission among
12 December 2008
consumer devices but medical
imaging systems, automotive collision
avoidance, UAVs, and so on.
Information about commercializing
the technology is available at the
Virginia Tech Intellectual Properties
website ( www.vtip.org), so feel free
to glom onto it.
NOISELESS AMP
DEVELOPED
Researchers at the National
Institute of Standards and
Technology (NIST, www.nist.gov)
and JILA ( jilawww.colorado.edu),
a joint institute of NIST and the
University of Colorado (CU) at
Boulder, have announced creation of
the first tunable “noiseless” amplifier.
Although the concept of noiseless
amplification isn’t new, this device is
said to offer improved performance
and is the first to be tunable (in the
range of 4 to 8 GHz). According to
an NIST article, “The rules of quantum mechanics say that the noise in
amplitude and phase can’t both be
zero, but the JILA/NIST amplifier
exploits a loophole stipulating that if
you measure and amplify only one of
these parameters — amplitude, in
this case — then the amplifier is
theoretically capable of adding no
noise. In reality, the JILA/NIST
amplifier adds about half the noise
that would be expected from measuring both amplitude and phase.”
PHOTO COURTESY OF M. CASTELLANOS-BELTRAN/JILA.
■ The JILA/NIST “noiseless” amplifier.
The device is made up of a long
line of magnetic sensors (starting on
the right in the photo). The sensors —
known as superconducting quantum
interference devices (SQUIDs), are
composed of aluminum oxide
sandwiched between two layers of
superconducting niobium, which
creates a “metametal” that selectively
amplifies microwaves based on
amplitude rather than phase. Each
amp contains 480 sensors in a 5 mm
niobium cavity. An injection of an
intense “pump tone” causes the
microwave power to oscillate at twice
the pump frequency. Only the part
of the signal that is synchronous with
the pump is amplified.
Practical applications are still in
the future, but it is said that the amp
could boost the speed and precision
of quantum computing, as well as
enhancing communication systems.
COMPUTERS AND
NETWORKING
MONSTER COMPUTING
GRID IN OPERATION
The worldwide furor was huge
as the first particle beams were
injected into the Large Hadron
Collider (LHC) in September, but an
interesting sideshow is the related
Worldwide LHC Computing Grid,
which claims the title of world’s
largest. The grid combines the power
of 140+ computer centers from 33
countries, allowing 7,000 scientists to
analyze LHC data. US contributions
to the grid are coordinated via the
Open Science Grid (www.open
sciencegrid.org), which also works
with other scientific research
communities including universities,
national laboratories, and computing
centers across the country.
The grid presently manages more
