Although magnetic-based circulators have reigned supreme for providing two-way communications on the same frequency channel, problems arise due to their large size, weight, and cost. To address those issues, researchers at the Cockrell School of Engineering at the University of Texas at Austin, developed a new radio-wave circulator that eliminates the need for magnets and magnetic materials.
Its lack of magnetic materials means a smaller footprint and less expensive materials, suiting the circulator for cellphones and other microelectronic systems. In fact, according to the research team, the circulator could double the useful bandwidth in wireless communications.
Full-duplex functionality—the ability to transmit and receive signals on the same frequency band at the same time—holds the key to its success. The new circulator mimics the way magnetic materials break the symmetry in wave transmission to selectively route radio waves, but instead of using magnetic bias, a traveling wave spins around the device. It can also be tuned in real time over a broad range of frequencies unlike traditional circulators.
Measuring 2 cm, the prototype device is more than 75% smaller than the wavelength of operation. Purportedly, it could be scaled down to as small as a few microns. The circulator’s design is based on commonly used integrated-circuit materials, including gold, copper, and silicon, which makes it easier to integrate into the circuit boards of current communication devices. The circulator’s scalability, however, could push its application into phased-array and radar systems for aircraft, ships, and satellites.