Investigation of Rectenna's Bandwidth for RF Energy Harvesting

This paper presents an enhanced rectenna with harmonic rejection for RF energy harvesting applications. Based on a wideband log-periodic antenna, the high-order harmonics at 4.9 GHz, 7.35 GHz, and 9.8 GHz can be suppressed by optimizing the sizes of the antenna's branches. A rectenna with harmonic rejection can be formed by combining this antenna with a 2.45-GHz rectifier. The RF-to-DC power conversion efficiency of this rectenna is measured and compared with a second rectenna without harmonic rejection capability. The comparison shows that the designed rectenna's efficiency is enhanced, and hence it is advantageous when used for the RF energy harvesting application.