Researchers in the Cockrell School of Engineering at the University of Texas at Austin have designed an antenna that can break reciprocity without requiring additional expensive electronic components.
Their work could have implications for service providers because the non-reciprocal antenna can be used to deliver faster, cheaper and clearer communications and enable sensors to pick up stronger signals.
In textbooks, the angular patterns for antenna transmission and reception have been assumed to be the same -- if the antenna opens a door to let signals out, signals can come back through that same door and leak toward the source. By breaking reciprocity, the UT Austin researchers' new antenna can independently control incoming and outgoing signals with large efficiency, according to the university.
Andrea Alù, associate professor in the department of Electrical and Computer Engineering, along with postdoctoral fellows Yakir Hadad and Jason Soric, discuss their non-reciprocal antenna's design and capabilities in the Proceedings of the National Academy of Sciences. Their article was published last month.
"Our achievement is that we break the symmetry between transmission and reception signals, so we are able to prevent the antenna from having to listen to reflections and echoes that affect the source," Alù said in a release. "We show that it is possible to efficiently overcome these constraints using temporally modulated traveling-wave antennas."
In the team's experiments, the researchers fed the antenna with two signals simultaneously: the radio-frequency signal that they want to transmit or receive, and a weak low-frequency modulation signal that slowly changes the properties of the antenna as the radio-frequency signal travels along it. The modulation breaks the inherent symmetry of the antenna in transmission and reception, overcoming the reciprocity constraints.
They say the main advantage of their technological advancement is the possibility of sending out a signal while keeping out noise and echoes that come back toward the antenna, enabling faster data rates and improved connections while requiring less bulky antenna systems. Besides telecom, the new antenna technology could be applied to sensors used in applications for health care and weather tracking, allowing the sensors to pick up stronger signals for more accurate data collection.
The researchers are now looking into how the concept may be extended to other applications such as optics. They envision that by pushing these concepts to higher frequencies, it will be possible to break a similar constraint affecting energy-harvesting devices such as thermophotovoltaic cells. The researchers believe that their antenna experiment, extended to the infrared part of the spectrum, may provide a route toward more efficient energy-harvesting platforms.
- see this release
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