A Rectifying Circuit With High-Efficiency DC and Harmonic Generations

Rectifying circuits are key components in wireless energy harvesting (WEH) systems. In this study, we propose a new circuit configuration that features simultaneous high-efficiency direct-current (DC) and second-harmonic (SH) generations. Based on a conventional single-series Schottky diode-based rectifying circuit, a bandpass filter is created and innovatively connected to the anode of the diode, which serves as an effective route to output the SH component produced by the diode, yet without sacrificing the DC generation. A prototype is fabricated and measured. The results show that when the input fundamental-frequency power is 19 dBm, the DC conversion efficiency is 55.0%; more importantly, the SH power reaches 9.8 mW, corresponding to a distinctive conversion efficiency of 12.3%. This is higher than previous works without using amplifiers or other active facilities, leading to a competitive overall efficiency of 67.3%. The enhancement of SH is of great significance in improving readout distance and communication quality if it is utilized as an echo signal in backscattering communications. Therefore, this simple and low-cost circuit can find potential applications in WEH and battery-free backscattering systems.