A novel, high-res radar could double as a health monitor

We all know that radars are used to spot and track aircraft, navigate ships from thunderstorms, and even observe space dust. But now, there is a new development that enables us to use radars on much smaller scales, such as the human body.

A research team from the University of Sydney has published a study outlining an improved radar that could be used on scales of inches. The improved radar is called advanced photonic radar, the ultra-high-resolution device is so sensitive it can detect an object’s location, speed, and/or angle in inches as opposed to feet. The novel advanced photonic radar could be used as a vital sign monitor for breathing and heart rate or to track movements in hospitals.

In the case of breathing, the radar could continuously detect a person’s chest rising. The usual method of monitoring this is strapping a monitor around a person’s chest. In the case of burn victims with sensitive skin, however, this is impractical. Therefore, the novel radar technology could offer a better alternative.

Professor Benjamin Eggleton, principal investigator for this research and Director of the University of Sydney Nano Institute said, “Our invention represents a breakthrough with the use of photonics (light particles). I’m excited about the potential non-traditional applications of this technology, regarding human movement. The important parameters that matter when you build a radar system are going to be the frequency of the radar, and the bandwidth over which the radar signal is,” 

Radar works by sending out a radio wave, and recording when it bounces off an object and returns to the source. The difference in time between pulse and return can be used to figure out how far away the object is. This is how air traffic controllers manage incoming flights, and military forces track craft in the air and at sea.

“For that traditional application, the frequency is relatively low – like 500 megahertz. Because all you need to know is: is it a big plane or a small plane?” says Eggleton.

Understanding the size of the object might be sufficient for air control towers, but if the radar is set at higher frequencies, it could return more information.

“If you can increase the frequency of the radar and go to higher frequencies – tens of gigahertz, 40 gigahertz, for example, you can then increase the bandwidth of the signal. Now that radar has a very high spatial resolution. So not only can you see the location with incredible precision, but you will actually map out the shape of the object with incredible precision,” explains Eggleton. 

High bandwidth radar is an existing concept – but up until now, it’s mostly been impractical because of the difficulties in implementation and the very high prices. The research team has avoided this obstacle by using photonics – the physical science of light waves.

“We use a photonic trick, basically, to generate this high bandwidth radar without requiring any high-speed electronics,” says Eggleton. “And that’s the magic.”

The advanced photonic radar system differs from conventional radar by using photonics, the device can pulse and receive a much broader range of frequencies without requiring any advanced high-speed electronics. This allows the advanced photonic radar to generate higher-resolution images in a format that is simpler and potentially much lower cost and see objects with a resolution down to 1.3 centimeters.

Research co-lead, Ph.D. candidate Ziqian Zhang said, “We hope to see real-world applications of this low-cost technology in the not-too-distant future.”

For the next step, the team plans to test their system on cane toads, before human participants. But unfortunately, animal ethics approval is slowing them down – not because of the danger posed to the toads, as there is none, but because of the complications involved in transporting, storing, and handling the toads. If the technology is deemed safe, and the research is undergoing ethics approval to proceed. And once an advanced prototype has been developed, the researchers claim that it could be miniaturized and built into a smartphone using a photonic chip.