Wideband High-Efficiency and Simple-Structured Rectifying Metasurface

In this communication, a wideband rectifying metasurface (RMS) for RF energy harvesting (EH) is proposed. By virtue of the two resonant modes of the paralleling metasurface (MS) resonator, it is not only the wideband feature can be obtained but also enables direct impedance matching between the high impedance diode and high impedance MS, eliminating impedance matching. A dc feed structure is proposed where each unit of the MS is connected by the chip inductors, and dc energy can be combined and exported directly, eliminating power combining networks. Then, a $6\times6$ array was designed and fabricated. Experimental results show that the proposed RMS system operates at 5.32–6.66 GHz with a fractional bandwidth (FBW) of 22.4%, and the peak efficiency is 74.5%. As a contribution to this work, RF energy on a broader frequency range can be captured by the proposed system with higher system efficiency, while maintaining a simple structure. This shows its great potential in wireless power transfer and indoor RF EH.