Throw a stone into water: right at the point of impact, the waves are chaotic — that's the near field. Farther out, they spread in smooth circles — the far field. This same principle governs antennas for terahertz communications — the future of super-fast internet.
Terahertz waves operate at frequencies hundreds of times higher than Wi-Fi, transmitting data almost at the speed of light. But they fade quickly in the air, so engineers pack antennas into tight arrays. In an ordinary room, scientists measured how the signal reflects off walls and furniture, and found that the slightest shift of the receiver dramatically changes the pattern. The signal seems alive. Then they created an algorithm that recognizes the type of wave — near or far — by the shape of its front, relying on the laws derived by Maxwell back in the 19th century.
An unexpected twist: at a distance of just two meters, 90% of the energy passes through the near field — those very chaotic splashes near the 'stone'. It was previously thought that communication only works in the far field, but now it's clear: the secret to super-high-speed transmission hides in the chaos up close.
For decades, the terahertz range was called the 'gap' due to a lack of instruments. Today, it's the hottest topic in radio engineering.
Volumetric holograms from science fiction will become reality with terahertz communications, which transmit myriads of data without delay.