Implementation of a PN junction rectifying diode in a metasurface for efficient electromagnetic energy harvesting

Summary form only given. Recently, it was demonstrated that metamaterials can be used to harvest ambient electromagnetic energy [1]. However, the choice of the rectifying circuit for highly efficient energy conversion of RF electromagnetic power to DC power remains an important challenge [2,3]. Therefore, it is important to design a metasurface integrating a rectifier circuit in combination with a proper matching impedance to optimize the power transfer.In this contribution, we present the design of a single-layer cut-wire metasurface [4] for the energy harvesting of RF electromagnetic waves with PN junction diodes embedded within each unit cell to channel the DC output power without the need for a bias voltage to trigger the functionality (Fig. 1(a)). By studying the characteristics of the diode-in particular the resistance and the threshold voltages of a Germanium diode and a Silicon diode- we find the most appropriate parameters for optimal power conversion and we obtain an efficiency of 50 % for incident waves with an amplitude corresponding to typical WiFi signals (Fig. 1(b)). This electromagnetic energy harvester works for a wide range of incident angles and exhibits a broad bandwidth in the microwave frequency.