New RF circulator to run rings around old technology
In the world of electronic components, there are many devices out there that do their job well and reliably, but are almost never heard of – even though they may be vital to equipment that plays a role in our technology-driven lives. The radio frequency (RF) circulator is just such a device: it has simply done its job as a nondescript box of gubbins buried in radio communications systems, quietly directing radio frequency signals to the places they should go. Now researchers at the University of Texas have given the RF circulator a makeover. Not only is the new prototype smaller, lighter, and cheaper, it’s also claimed to be easily adapted to different frequencies on the fly, which is something the old style circulator cannot do.
A standard RF circulator is a three-port ferromagnetic passive device used to control the direction of signal flow in a circuit. In simple terms, magnetic fields are used to channel electromagnetic flow in a specific direction, thereby providing two-way communications on the same frequency channel by allowing, for example, two transmitters to use the same antenna. The downside, according to the researchers, is the bulk and weight of a standard circulator.
The new RF circulator uses a circuit created from inexpensive, surface-mount, active semiconductor components. The team predicts that the current prototype is just a start to the miniaturization; the size of future RF circulators may be scaled down much further to sub-miniature versions of the components on an integrated circuit. As a result, the researchers say that this should lead to improvements in cost and size and allow the incorporation of circulators in cellphones and other microelectronic communications devices that may result in faster downloads, fewer call drop-outs and clearer communications.
“We envision micron-sized circulators embedded in cellphone technology,” said Nicholas Estep, lead researcher and a doctoral student in the Department of Electrical and Computer Engineering. “When you consider cellphone traffic during high demand events such as a football game or a concert, there are enormous implications opened by our technology, including fewer dropped calls and clearer communications.”
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