Researchers from Georgia Tech have developed a device that lets them harness the over-capacity of 5G networks to power IoT devices that otherwise rely on batteries. Typically, to utilize enough power to feed low-power devices at long ranges, a large aperture antenna is required. Only those large antennas have a narrowing field of view (FOV), limiting their operation if the antenna isn't near a 5G base station. This means trying to harvest any power to supply IoT devices in the field is almost nonexistent.
To get around that problem, the researchers developed a Rotman lens-based rectifying antenna capable of millimeter-wave harvesting at 28 GHz, with high efficiency in all directions. "With this innovation, we can have a large antenna, which works at higher frequencies and can receive power from any direction, stated Jimmy Hester, CTO of Atheraxon, a spinoff of Georgia Tech. "It's direction-agnostic, which makes it a lot more practical." The Rotman lens operates similar to an optical lens; only it provides six fields of view simultaneously in a pattern that's reminiscent of a spider web. When the shape of the lens is tuned, it provides a structure with one curvature angle on the beam-port side and another on the antenna side.
Tuning allows the system to map a set of selected radiation directions to an associated set of beam-ports, where the lens is then used as an intermediate component between the receiving antennas and rectifiers for 5G energy harvesting. The researchers demonstrated their lens and managed to achieve a 21-fold increase in harvested power over conventional antennas while maintaining identical angular coverage. The new system could be utilized for viable long-range, mm-wave 5G-powered RFID for wearable and universal IoT applications.