New semiconductor chip helps smartphone cameras 'see through' objects?

The prototype chip consists of a three-pixel sensor array that transmits and receives high-frequency radio signals in the millimeter wave (mmWave) band of the electromagnetic spectrum. The signals reflected from the target object are then amplified and mixed by onboard components, allowing the object's shape to be displayed on the screen.

In tests, the chip was able to detect an object behind cardboard at a distance of about 1 centimeter. The researchers published their findings on January 5 in the world's leading journal of science and technology (IEEE Transactions on Terahertz Science and Technology).

It took 15 years of research and 100 million times more pixel efficiency to make the chip small enough to fit into a mobile device, the researchers said. In the future, smartphones equipped with the chip could detect the contents of envelopes or packages, or be used to find screws, wires or cracked pipes behind walls.

“We designed the chip without lenses or optical components so that it can fit into a mobile device,” said Wooyeol Choi, an assistant professor of electrical engineering at Seoul National University and co-author of the paper in a statement. “The pixels, which create images by detecting reflected signals from a target object, are 0.5-millimeter squares, approximately the size of a grain of sand.”

In addition to seeing through walls and inside envelopes, the new imaging technology could have applications in medicine and health care, the researchers say. They liken the technology to that already used in passenger scanners used at airports, although they note that their imaging chip does not use radio waves in the microwave band like the technology used in passenger scanners.

Instead, the imaging chip uses radio waves at a frequency of 300 gigahertz in the millimeter wave (mmWave) band of the electromagnetic spectrum. This band lies between microwaves and infrared and is considered safe for humans.

“This technology is similar to the X-rays Superman uses to see through solid objects, including clothes, flesh, and even metal. Of course, we use signals at 200 gigahertz to 400 gigahertz instead of X-rays, which can be harmful to humans,” added Kenneth O, professor of electrical engineering at the University of Texas at Dallas.

Additionally, unlike Superman's X-rays, the imaging technology used in this chip can only work at very close range, about 2.5 centimeters from the object being scanned. This means that thieves will not be able to secretly scan the contents of a user's bag or clothing without the user knowing, the researchers said.

The next version of the chip will be designed to scan objects further away, possibly up to 12.7 centimeters, allowing it to capture smaller objects better, according to the researchers.