New wireless technology could make communications more secure

NIST is studying the technology

Researchers at the National Institute of Standards and Technology have theoretically verified a method for using electron spin to generate radio waves that could make wireless communications more secure and more efficient in “noisy” environments.

The work, reported in the journal Physical Review, is a mathematical evaluation of a class of radio frequency oscillator called spin torque oscillators.

“It’s not even a prototype; it’s just a theory,” said physicist Mark Keller at the NIST lab in Boulder, Colo. But the equations showed that the theory should work using materials that already exist.


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If they work as expected, current passed through a magnetic sandwich could produce a stationary wave called a soliton whose oscillation could be used to generate radio waves. The torque device should be able to produce waves from about 1GHz to about 50GHz, which is the band used for mobile wireless communications.

“These things have a frequency that changes with magnetic field, but not with the current,” as current RF oscillators do, Keller said. This would let the generator create stable frequencies that could be shifted quickly and over a wide band. This would be valuable in environments with a lot of interference because the device could shift frequencies to quickly find the most effective one. It also could be used for spread-spectrum or frequency-hopping security in which a signal changes frequency quickly to avoid detection or jamming.

“But it has a drawback because it is so small that it tends to be noisy,” Weller said. A tiny device operating at room temperature, “it gets kicked around by thermal fluctuations,” and generates stray RF waves as noise that can interfere with operation.

For this reason the advantages of frequency hopping in any final product would have to outweigh the disadvantages of its noisiness, which means that the electron spin devices are not likely to replace current technology used in cell phones, Wi-Fi and other wireless communications.

Keller said the research team hopes to fabricate the materials needed for a practical test of the theory but that any practical application still is years away. “If everything worked well, it might be five years,” he said. But that would depend on the demand for the specialized tool and the amount of money customers would be willing to spend on it. If the military saw value in it for secure battlefield communications, that could spur development, he said.



About the Author

William Jackson is freelance writer and the author of the CyberEye blog.

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