Effective wireless low-power transmission using a phased array antenna

In this study, we perform a low-power wireless power transfer experiment to efficiently transfer energy using a phased array antenna (PAA). At the transmitting end, we used a 4 × 4 PAA consisting of left-handed transmission line-based compact phase shifters and inset-feed microstrip patch antennas. The PAA used has a -30° to 30° tilting beam range with a gain ranging from 6.42 to 7.09 dBi. At the receiving end, we used an 8.9-dBi single Yagi-Uda rectenna at a distance of 0.8 m from the PAA and measured the converted DC powers to be between 1.5-2.2 mW for the tilting beam range. In the experiment, we limited the effective isotropically radiated power to 3 W because of concerns regarding human body safety.