Reflective 6G Tiles Could Solve Millimeter-Wave Coverage Problems

The promise of 6G networks includes remarkably fast wireless speeds, but the technology faces a major challenge: the high-frequency radio signals it relies on struggle to pass through walls, furniture and other obstacles. Engineers have now developed a potential solution using inexpensive, 3D-printed reflective tiles that redirect signals around barriers.

The next generation of mobile technology is expected to depend heavily on millimeter-wave electromagnetic spectrum. These short-wavelength signals can carry large amounts of data, but they are easily blocked by solid objects. As a result, millimeter-wave networks can suffer from weak or patchy indoor coverage.

This behavior differs from lower-frequency signals used by Wi-Fi and older cellular technologies, including 4G and some 5G networks, which generally pass through obstacles more effectively. Improving indoor coverage will be essential if 6G and other millimeter-wave applications are to work reliably in homes, offices and public spaces.

Researchers believe they have found a low-cost workaround: thin, 3D-printed tiles that reflect millimeter-wave signals around obstacles instead of trying to transmit through them. The team described the technology, known as FlowForm, in a study published in the Association for Computing Machinery and presented the findings at the ACM SIGCOMM 2026 conference in Denver on Aug. 19.

How reflective tiles could improve 6G coverage

6G networks are expected to begin rolling out in the 2030s. Their maximum theoretical data rate could reach 1 terabit per second — nearly 3,000 times faster than average 5G speeds. Before that potential can be realized, however, engineers must overcome the problem of wireless signals being blocked by physical barriers.

Each 6-by-6-inch (15-by-15-centimeter) FlowForm tile contains thousands of precisely engineered features that are smaller than the wavelength of the signal. These structures passively redirect incoming millimeter waves in a controlled direction.

Once installed on a wall or ceiling, the tiles require no power, wiring or software updates. Their passive design could make them easier and less expensive to deploy than electronically controlled signal-boosting systems.

FlowForm tiles perform two complementary functions, inspired by the way water moves through a branching river system. Some tiles relay signals along longer “main” paths through a room or around obstacles. Other tiles redirect signals outward, extending coverage into areas where people are likely to use the network.

“Our work demonstrates that a collective set of passive surfaces can make mmWave networks robust in real-world environments,” said Xinyu Zhang, a study co-author and professor of electrical and computer engineering at the University of California, San Diego.

In tests across five real-world indoor environments, including cluttered offices and irregularly arranged rooms, the reflective tiles nearly doubled the average data rate and more than doubled coverage in difficult areas. The researchers said the results were comparable to those achieved with active reconfigurable intelligent surfaces.

Active systems use electronically controlled panels that require power and can cost thousands of dollars each. By comparison, the new passive tiles are estimated to cost about $2 apiece, potentially making them a more affordable option for improving indoor 6G and millimeter-wave wireless coverage.

The system can also support users who are moving through a room. Wireless access points already search for optimal signal paths many times per second, and the tiles provide multiple reflection angles. This means a usable signal route should remain available as a person changes position. The researchers say the tiles could be added to existing networks without requiring new hardware or software.

The research team has applied for a provisional patent and is seeking partnerships with companies interested in commercializing the technology. If further development succeeds, inexpensive passive reflectors could help overcome one of the biggest obstacles facing future 6G networks: delivering reliable, high-speed millimeter-wave connectivity indoors.