UT professor develops new antenna design

Raza Retiwala

A team led by associate professor Andrea Alù in the Cockrell School of Engineering has developed a new design that might one day make the antenna in students’ phones faster and more efficient. 

This team’s new antenna prototype is special because it breaks antenna reciprocity. This basic quality of antennas allows rogue signals into an antenna through the same channel that lets signals out. 

These rogue signals can interfere with any outgoing signals, leading to background noise or faulty data collection.

Antennae signals are similar to light traveling through a piece of clear glass. If light can get out, it can also come in. 

“If the antenna transmits well in a certain direction, then it will also receive with exactly the same efficiency, from that direction and frequency,” said Yakir Hadad, a research fellow who joined Alù in 2014. 

In the past, scientists who wanted to eliminate reciprocity in antennas were forced to use isolators made of magnets to divert or cancel out any frequency the antenna received. These isolators added additional weight to already bulky instruments. 

“Magnetic materials for non-reciprocity is kind of a brute force method. This is much more elegant,” said Jason Soric, a postdoctoral fellow in Alù’s lab. 

The design by Alù changes the need for isolators. It allows signals to leave without letting any rogue signals in. This prevents interference when antennas send information out. The clear window is now mirrored glass. 

This new antenna handles incoming and outgoing signals separately, which increases the efficiency of electronics that use antennas. The lack of signal interference allows the antenna to send clearer messages. It also allows the antenna to handle less data, leading to faster and more reliable transfer rates. 

Hadad and Alù developed the theory behind the antenna, while Soric built and tested the antenna by hand. 

“In a project such as this, many details needed to be worked out even though the theory was already developed,” Soric said. “Yakir had already developed the theory for non-reciprocal antennas, and I was brought in to design and test the antenna.”

Alù’s researchers learned many lessons that extend beyond simple antenna construction. Reciprocity can also influence infrared technology, which plays a role in energy harvesting. 

Though the current version of the antenna is in its early stages, Soric said future improvements might allow the design to be used in mass produced devices, such as phones. 

“Anytime you come up like an idea like this and it can implemented on a chip with others electronics, … that’s when things get interesting.” Soric said.