Your typical Wi-Fi router sends the same signal in all directions, which can create both performance and security problems. But a multi-university team of researchers has developed a cheap fix: a 3D-printed reflector that's covered in aluminum foil to direct stronger signals to places where they're needed and redirect signals away from areas that are more vulnerable to hacking.

Printing a reflector that's custom designed for a specific interior space takes only 23 minutes and only costs around $35, according to the researchers. They presented their findings yesterday at the Association for Computing Machinery's BuildSys conference in Delft in the Netherlands.

Their research builds on previous work in which they demonstrated how an ordinary soda can, cut open with the top and bottom removed, could be placed behind a Wi-Fi router to boost wireless signals in some directions.

Outperforms Commercial Alternatives

While directional Wi-Fi antennas are available commercially, they tend to be limited in how well they boost signals in the desired direction or they're more sophisticated but prohibitively expensive, the researchers noted in their study. By contrast, a 3D-printed reflector can be custom designed to maximize Wi-Fi performance in any particular space for a relatively small investment of time and money.

"With a simple investment of about $35 and specifying coverage requirements, a wireless reflector can be custom-built to outperform antennae that cost thousands of dollars," Xia Zhou, an assistant professor of computer science at Dartmouth College, said in a school statement.

Other researchers involved in the study included Dartmouth's Xi Xiong, Ethan Yu, and Nisha Kumari; University of Washington's Justin Chan; University of California-Irvine's Ardalan Amiri Sani; and Columbia University's Changxi Zheng.

By optimizing the directions in which wireless signals are sent, the 3D-printed reflector improved throughput by just over 55 percent to areas where better coverage was needed, while reducing throughput by more than 63 percent to places where coverage wasn't needed, the researchers said.

Looking Ahead to Future Improvements

The customized reflector provides a number of benefits over an unenhanced Wi-Fi router, the research team noted. It's easy for non-technical users to deploy, and inexpensive to replace when coverage needs change. It can also improve security by reducing signals to areas, such as windows, that provide opportunities for malicious actors to hack into the local network.

"Such physical confinement of wireless signals serves as a [complementary] method to existing network security measures, such as encryption, and hence raises the barrier for attackers," the researchers wrote in their study. In effect, by directing signals away from some areas, the reflector creates a sort-of "virtual wall" for Wi-Fi routers.

Despite these benefits, the 3D-printed reflector still has some limitations. Because it's a static shape, it won't work as effectively if the environment changes significantly in any way -- for example, if the router is relocated or furniture arrangements are dramatically changed. The enhanced performance is also limited by wireless signal wavelength.

In the future, those problems might be addressed by using millimeter waves or visible light signals that can be reflected or blocked more effectively, and by creating reflectors from materials that can be automatically reshaped to adapt to changing signal requirements, the researchers noted.