Design of a High-Efficiency RF Energy Harvesting System

In this paper, a multi-tone RF energy harvesting system (RFEHS) is designed to operate at ISM bands of 915MHz and 2.45GHz. Thanks to its duplexed input design configuration, the RFEHS offers 40.53% efficiency at minimal output impedance value of 5.7k$\Omega$. To mimic real applications of the proposed design, wideband input RF is applied at –20dBm power level to the multi-tone RFEHS, which results into 2.33V output voltage at a load impedance of $3.98\mathrm{k} \Omega$. This is more than four times better than a similar single-tone system with the same load impedance. Therefore, the approach can be extended to multiband systems to offer yet more output voltage and higher efficiencies at multiple frequencies as well.