A Flexible Dual-Band Rectenna With Full Azimuth Coverage

This paper presents a novel cylindrical shaped dual-band flexible rectenna capable of harvesting RF energy from number of RF sources available in the entire azimuth plane. The proposed configuration is an array of four identical dual-band rectenna subsystems, printed on the lightweight flexible substrate. Here, each rectenna subsystem comprises of a dual-ring shaped dual-band monopole antenna and a dual-band rectifying circuit. The designed topology is good for popular bands of LTE 1.8 GHz and Wi-Fi 2.45 GHz. The robustness of the designed antenna in the proposed cylindrical shaped rectenna is also verified by testing it for different bending angles in the H-plane by simulation as well as measurement. The bending performance is tested for the antenna using S11 and farfield radiation pattern. Further, for extracting maximum RF signals in the entire azimuth plane, these four identical antennas are backed by a wide-band artificial magnetic conductor (AMC) placed in the inner region of the cylinder. The fabricated single rectenna unit is capable of converting power with 40% efficiency at very low input RF power -12 dBm. Finally, the overall rectenna array is fabricated and validated through measurements using two different test antennas as a RF sources in the real environment of lab. The proposed light weight, rectenna printed on a flexible substrate can extract RF signals from a number of randomly distributed RF sources simultaneously, while maintaining the overall compact configuration.