Compact High-Efficiency Broadband Rectifier Based on Coupled Transmission Line

In this brief, a compact high-efficiency broadband rectifier with an extended range of input power is proposed for the applications in wireless energy harvesting (EH). In the rectifier, a coupled transmission line is connected in series with a Schottky diode to compensate its capacitive reactance, compress its impedance variation when the frequency or input power varies. The coupled transmission line facilitates the impedance matching circuit and reduces the insertion loss. High RF-dc conversion efficiency will be achieved consequently. A rectifier is fabricated and measured based on analysis and simulation on the coupled transmission line. The measured results show a good agreement with the simulation results. The rectification efficiency of the rectifier is over 70 % from 1.6 to 2.8 GHz (a bandwidth of 54.5%) with the input power range from 11 to 14 dBm. The efficiency remains above 50% from 1.5 to 2.85 GHz with input power from 5 to 18 dBm,and over 40% within 1.7-2.8 GHz when the input power decreases to 0 dBm. The maximum measured efficiency is 78.63% at an input power of 16 dBm.