Circularly Polarized Meandered-Loop Antenna for Ambient RF Energy Harvesting System

In this paper, the circularly polarized (CP) antenna is proposed based on the loop antenna for ambient RF energy harvesting (RFEH) applications. This loop antenna is meandered to achieve a compact size of 30 mm × 50 mm. The proposed CP meandered-loop antenna has a measured bandwidth of 150 MHz at – 10 dB with a center frequency of 2.14 GHz for 3G and 4G technologies. A maximum of 62 % RF-DC conversion efficiency is obtained using the proposed CP antenna and a load of 1.2 KΩ when the power of the incident wave is 0 dBm.