Novel Microwave Rectifier Optimizing Method and Its Application in Rectenna Designs

In this paper, a fast converging and computationally efficient iterative method for rectifier optimization is proposed. The method is carried out in the advance design system. By taking into account the interaction between the received power and output performance, the impedance of the Schottky diode when operating optimally in the rectifier can be precisely obtained once the spice model, operating frequency, and the dc load value are given. The impedance can be used to design the matching to minimize the insertion loss. The time and effort needed for the method are smaller than the optimizing tools provided in ADS and other related works, and the reliability of simulation is enhanced. For demonstration, a compact rectifier operating at 5.81 GHz is optimized, fabricated, and measured. The measured power conversion efficiency exceeds 40% at input power level ranging from −5.5 to 12.5 dBm, and the optimum reaches 69.4% at 8.2 dBm. Good agreement can be found between simulated and measured data. Finally, the rectifier is integrated with a high-efficiency antenna to form a rectenna design; 69.2% optimal efficiency is obtained at 0.41 mW/cm 2 power density in the measurement.