Walls can guide millimeter waves instead of blocking them.

Indoor wireless signals at millimeter-wave frequencies struggle because walls usually block or bounce them. Today's systems steer beams around these barriers. Researchers tested a completely different idea: using walls to guide signals instead of dodging them. They focused on lateral waveslateral wavesA type of wave that travels along the boundary between two different materials, like air and a wall., which are signals that travel directly along the boundary where two different materials meet. Instead of vanishing quickly like normal reflections, these boundary-hugging waves lose strength at a steady, algebraic rate as they travel. Scientists had seen this effect at lower frequencies in nature, but never tested it with high-frequency millimeter waves on building materials. By testing waves grazing along a wall, the team confirmed these lateral waves actually exist indoors, offering a fresh way to route wireless connections along surfaces.

Why it matters

Indoor millimeter-wave signals usually die if a wall blocks the direct path. This research shows that walls themselves can carry the signal along their surface, offering a new way to reach devices around corners. It could mean fewer dead zones in homes and offices without adding extra transmitters.

Questions answered