Transmission Lines-Based Impedance Matching Technique for Broadband Rectifier

A high-efficiency compact broadband rectifier is developed for wireless energy harvesting. A novel three-stage impedance matching technique is utilized in a broadband rectifier design to achieve high conversion efficiency with a compact size. In the rectifier, a low loss impedance matching technique is initiated by employing a linearly tapered transmission line for controlling the impedance curve at the required input power level, followed by two stages to make a circular impedance curve for wideband impedance matching. Both theoretical analysis and numerical simulations of the proposed rectifier are performed. For validation, a prototype is fabricated and demonstrated a broadband performance with a fractional bandwidth (FBW) of 74% (from 1.12 to 2.43 GHz) and power conversion efficiency of more than 50% at a 5 dBm input power level. Moreover, the rectifier can reach an efficiency of more than 50% extending from 0.97 to 2.55 GHz (FBW = 90%) at the input power of 10 dBm, which is the highest bandwidth reported under this condition. This low complexity design is suitable for realizing broadband rectifiers for wireless energy harvesting (WEH) applications.