Exploiting the Mutual Coupling Effect on Dipole Antennas for RF Energy Harvesting

Energy harvesting is an essential technology for future Internet of Things (IoT) networks. In this letter, the advantage of the mutual coupling effect for radio frequency (RF) energy harvesting is presented by analyzing the equivalent circuit model and conducting two half-wavelength dipole antenna array experiments. When mutual coupling exists with the spacing of antennas near half a wavelength, the total received power can be as much as 5.10 μW, 1.47 times larger than the value without mutual coupling, showing that the received power of the half-wavelength dipole antenna can be increased by exploiting mutual coupling. In addition, based on theoretical analysis, we attempt to generalize the mutual coupling effect for more than two dipole antennas. Analytical results show that the received power gain with mutual coupling can be more than 50%, compared to the uncoupled case.