Electronic components news

SiGe Semiconductor has released a trio of 802.11g RF front-end modules with different power/performance trade-offs.

The SE2521A60 is aimed at PC cards and is capable of +19dBm output power with an error vector magnitude (EVM) of less than three per cent while operating in 802.11g mode, or +23dBm in 802.11b mode while meeting all ACPR requirements. The device consumes 195mA in 802.11g mode.

The lower consumption A40 version is for embedded WLANs including Wi-Fi VoIP phones, with figures of +18dBm at 150mA in 802.11g mode or +22dBm for 11b. A high power version, the A80, for routers and access points provides +20dBm(11g) or +20dBm (11b).

Each device also integrates a power detector with 20dB of dynamic range, and a digital enable control for transmitter on/off control. The power detector boosts performance by minimising mismatch to only 1.5 dB of variation over a 2:1 antenna mismatch, said the firm.

www.sige.com

Signal processing software firm The Mathworks has pledged to support UK students with a fund for undergraduates and PhD students.

The firm said it would provide a 'studentship' for an undergraduate or PhD student at Oxford and another at Cambridge every three years.

Sham Ahmed

"Last month the UK's Science Minister Lord Sainsbury called on industry to highlight career opportunities in engineering," said Sham Ahmed, UK MD at the firm.

"I couldn't agree more - The MathWorks has selected the UK universities which feature highest in the worldwide rankings and we are determined to show that there are lucrative careers for our brightest engineering and mathematical talent outside the financial markets."

Payment of fees and grants is worth £350,000 over the next 12 years, claimed the firm, while the sponsored students will also be able to work at the firm during holidays.

The Mathworks is working with the Control Group in the Cambridge Department of Engineering and the Oxford Computing Laboratory. It will also fund two final year undergraduates with a £3,000 bursary to work on a relevant project.

www.mathworks.co.uk

MIT scientists have created a new type of matter, a gas of atoms that shows high-temperature superfluidity.

The work is closely related to the superconductivity of electrons in metals and may help solve questions about high-temperature superconductivity, which has widespread applications for magnets, sensors and energy-efficient transport of electricity, said Wolfgang Ketterle, a Nobel laureate who heads the MIT group and who is the John D. MacArthur Professor of Physics at the school.

According to MIT, research groups around the world have been studying cold gases of so-called fermionic atoms with the ultimate goal of finding new forms of superfluidity. A superfluid gas can flow without resistance and can be clearly distinguished from a normal gas when it is rotated.

A normal gas rotates like an ordinary object, but a superfluid can only rotate when it forms vortices similar to mini-tornadoes, MIT explained, adding that this gives a rotating superfluid the appearance of Swiss cheese, where the holes are the cores of the mini-tornadoes.

"When we saw the first picture of the vortices appear on the computer screen, it was simply breathtaking," said graduate student Martin Zwierlein, recalling the evening of April 13, when the team first saw the superfluid gas. For almost a year, the team had been working on making magnetic fields and laser beams very round so the gas could be set in rotation, he reported.

"In superfluids, as well as in superconductors, particles move in lockstep. They form one big quantum-mechanical wave," added Ketterle. Such a movement allows superconductors to carry electrical currents without resistance.

The MIT team was able to view these superfluid vortices at extremely cold temperatures, when the fermionic gas was cooled to about 50 billionths of a Kelvin, very close to absolute zero (-273°C or -459°F).

"It may sound strange to call superfluidity at 50 nanokelvin high-temperature superfluidity, but what matters is the temperature normalised by the density of the particles," Ketterle said. "We have now achieved by far the highest temperature ever."

Scaled up to the density of electrons in a metal, the superfluid transition temperature in atomic gases would be higher than room temperature, he added.

Broken down, the MIT team observed fermionic superfluidity in the lithium-6 isotope comprising three protons, three neutrons and three electrons. Because the total number of constituents is odd, lithium-6 is a fermion. Using laser and evaporative cooling techniques, the team cooled the gas close to absolute zero.

They then trapped the gas in the focus of an infrared laser beam; the electric and magnetic fields of the infrared light held the atoms in place. The last step was to spin a green laser beam around the gas to set it into rotation. A shadow picture of the cloud showed its superfluid behavior: The cloud was pierced by a regular array of vortices, each about the same size, MIT reported.

The work is based on the group's earlier creation of Bose-Einstein condensates, a form of matter in which particles condense and act as one big wave.

The superfluid Fermi gas created at MIT, said the school, can also serve as an easily controllable model system to study properties of much denser forms of fermionic matter such as solid superconductors, neutron stars or the quark-gluon plasma that existed in the early universe.

The MIT research was supported by the National Science Foundation, the Office of Naval Research, NASA and the Army Research Office.