Cooperative Integration of RF Energy Harvesting and Dedicated WPT for Wireless Sensor Networks

With an advance of semiconductor technology, RF energy harvested from ambient becomes more and more promise to facilitate low-power electronics. However, such energy is too low to activate a high-power module, constraining its widespread in wireless sensor networks (WSNs). To embed an ambient energy harvesting into WSNs, its cooperative integration with a dedicated wireless power transfer (WPT) is proposed. Therefore, low-power electronics can be sustained by ambient energy, while high-power modules can be activated by the dedicated WPT. A low-threshold rectifier is exploited to capture and rectify all matched ambient energy, while reflecting almost unmatched dedicated incidence. A low-loss and small-size circulator is employed to channel the two various energy flows, enabling a compact rectenna. The proposed integration is theoretically analyzed and experimentally validated, which is suitable for WSNs applications.