A 3D-printed antenna could turn high-frequency 5G signals into a wireless power source, potentially eliminating the need for batteries in low-power IoT devices, according to researchers at Georgia Tech.\n\n5G resources\n\nWhat is 5G? Fast wireless technology for enterprises and phones\nHow 5G frequency affects range and speed\nPrivate 5G can solve some problems that Wi-Fi can\u2019t\nPrivate 5G keeps Whirlpool driverless vehicles rolling\n5G can make for cost-effective private backhaul\nCBRS can bring private 5G to enterprises\n\n\nThe antenna, which the researchers call a mm-wave harvester, is about the size of a playing card and has visible circuitry printed on it. It uses a technology called a Rotman lens as a waveguide to focus multiple beams of millimeter-wave electromagnetic radiation used in 5G into a coherent whole.\nThe technology was previously best known as a component of phased-array radar systems, allowing it to see targets in multiple directions without physically moving the antenna system. It was invented in the 1960s by US Air Force and MIT researcher Walter Rotman.\n\u201cPeople have attempted to do energy harvesting at high frequencies like 24 or 35GHz before,\u201d said Aline Eid, a senior researcher a Georgia Tech\u2019s ATHENA lab in the School of Electrical and Computer Engineering. The shortcoming of the previous iterations was it only worked if the lens was oriented directly toward the transmitter. That made it difficult to position correctly and ruled out using it if the device it was powering moved around.\nIt also helps that millimeter-wave 5G signals are much more energy-dense than previous generations of licensed wireless technology, making them more suitable for energy harvesting.\nThe Georgia Tech team\u2019s design works more like an optical lens with six simultaneous fields of view, thanks to different curvature angles on the beam-port and antenna sides of the device. This allows the system to map multiple 5G signals at the same time, focusing them on the lens and power rectifiers to transformation the gathered signals into usable electrical energy. The result is that the system can generate 21 times as much power as a non-Rotman-based system, while being relatively simple to produce.\nManos Tentzeris, a professor at Georgia Tech\u2019s School of Electrical and Computer Engineering, said that the forthcoming ubiquity of 5G means that the Rotman lens-based technology could wind up powering huge numbers of IoT devices.\n\u201cThe fact is 5G is going to be everywhere, especially in urban areas,\u201d he said. The antennas could save a lot of money if IoT devices don\u2019t have batteries that die and need to be swapped out. \u201cYou can replace millions, or tens of millions, of batteries of wireless sensors, especially for smart-city and smart-agricultural applications.\u201d\nThe system isn\u2019t without its drawbacks, however. For one thing, it\u2019s still in the experimental stages, with no data available on when it might become available for commercial use. For another, it\u2019s still quite short-ranged--the experiments centered on a harvesting range of less than three meters, with a theoretical maximum of 16.\nNevertheless, the potential applications for the fast-growing world of IoT are hard to overemphasize. Statista predicts that 5.4 billion IoT devices will be in use by 2025 in North America alone, and with further development of the Georgia Tech system\u2019s effective range, many of them could be powered by 5G signals.