Design Guidelines for Voltage Doubler Circuits with Transmission Line Impedance Matching Networks for RFEH Applications

RF Energy Harvesting (RFEH) is the ideal substitute for traditional batteries for continuously powering the sensor networks situated in remote locations. An appropriate Voltage Doubler circuit (full-wave rectifier circuit) with high Power Conversion Efficiency (PCE) is required for this purpose. This paper gives guidelines for the design of voltage doubler circuits (rectifiers) utilizing two different transmission line (Tline) impedance-matching networks. Schottky diodes were used for rectification and two impedance-matching networks (IMN) were designed using the transmission lines. The two IMNs differ in their topologies and hence are termed Pi-section and T-section networks. The T-section network was found to give a much higher return loss. The proposed rectifiers operate at 900 MHz over a wide range of RF input power levels varying from -20 dBm to 30 dBm. With the T-section IMN, the voltage doubler offered a maximum PCE of 53% at an input power level of 20 dBm and a load resistance of 1 M Ohm. The DC output voltage was found to be 2.53 V.