New circuit could double speed of smartphones

Your smartphone and other compact wireless devices could soon receive data twice as faster, thanks to a tiny new inexpensive circuit developed by researchers.
Researchers at The University of Texas at Austin created the radically smaller, more efficient radio wave circulator that could be used in cellphones and other wireless devices.
The circulator has the potential to double the useful bandwidth in wireless communications by enabling full-duplex functionality, meaning devices can transmit and receive signals on the same frequency band at the same time.
The key innovation is the creation of a magnetic-free radio wave circulator.
Since the advent of wireless technology 60 years ago, magnetic-based circulators have been in principle able to provide two-way communications on the same frequency channel, but they are not widely adopted because of the large size, weight and cost associated with using magnets and magnetic materials.

Freed from a reliance on magnetic effects, the new circulator has a much smaller footprint while also using less expensive and more common materials.

These cost and size efficiencies could lead to the integration of circulators within cellphones and other microelectronic systems, resulting in substantially faster downloads, fewer dropped calls and significantly clearer communications.
The team of researchers, led by Associate Professor Andrea Alu, has developed a prototype circulator that is 2 centimetres in size - more than 75 times smaller than the wavelength of operation.
The circulator may be further scaled down to as small as a few microns, according to the researchers. The design is based on materials widely used in integrated circuits such as gold, copper and silicon, making it easier to integrate in the circuit boards of modern communication devices.

"We are changing the paradigm with which isolation and two-way transmission on the same frequency channel can be achieved. We have built a circulator that does not need magnets or magnetic materials," Alu said.
The device works by mimicking the way magnetic materials break the symmetry in wave transmission between two points in space, a critical function that allows magnetic circulators to selectively route radio waves.
With the new circulator, the researchers accomplish the same effect, but they replaced the magnetic bias with a travelling wave spinning around the device.
Another unique feature is that the new circulator can be tuned in real time over a broad range of frequencies, a major advantage over conventional circulators.

The research was published in the journal Nature Physics.