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Dec. 1, 2003 — The results of a project funded by a $1.2 million federal defense grant could send a clear signal to developers of next-generation military and commercial communication systems.
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The Defense Advanced Research Projects Agency announced the grant in October to a University of California, Irvine, professor to make light and low-cost antennas based on radio frequency (RF) MEMS. Such technology could provide satellite TV in a car, and eventually, laptops and other commercial products.
Electrical engineer Franco De Flaviis is creating the antennas using technology he developed at UC Irvine. The approach involves simultaneously making an array of antennas and a phase shifter, which adjusts and directs the antennas. The system saves money by fabricating the parts on a plastic printed circuit board instead of expensive semiconductor materials, and eliminating the need to connect pieces later in the process.
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De Flaviis said the antenna array delivers a stronger, more focused signal than a single antenna, but the size and cost of such integrated systems prevented their use outside of the military. Today’s satellite dishes are large because they need enough gain to get the signal from the satellite, and have a fixed beam — meaning they can be pointed in only one direction.
“It’s quite impractical to have that kind of antenna on the car,” he said. “Even if you could find a way to hide it, the car moves and you lose your signal.”
With the phased-array system, he said, a user can move the beam and search for the signal in real time. The technology is not new; it has been used in heavy-duty vehicles and aircraft such as jet fighters, tanks and trucks. De Flaviis said the breakthrough comes in decreasing the size, weight and cost of such systems to make them attractive for light vehicles and electronic devices.
He also said a phased array antenna could improve the performance and save space on a cellular tower, which now uses three fixed-beam antennas. The system could replace those with a single system that can redirect its beam to find the best signal in milliseconds.
The antennas will be made in the UC Irvine’s Integrated Nanosystems Research Facility (INRF), and undergo testing inside the university’s Microwave Lab. The three-year project also includes G.P. Li, INRF director and electrical and computer engineering professor; and Mark Bachman, INRF’s assistant director.
The goal of the DARPA contract is to build a general-purpose prototype. But De Flaviis’ team also is working with the U.S. Air Force on a specific prototype that could become part of an antenna system for an airplane.
Overall, he said, the biggest potential benefit of his team’s efforts could be to stakeholders of the radio spectrum — the range of frequencies for communication that is limited and therefore costly: “It’s always more expensive to buy more spectrum,” he said. “The phased array offers better usage of the RF spectrum that you own.
“Anything that can provide better usage … is always appealing to a company in that area.”