A 2.4-GHz 10-W Class Bridge Rectifier and Its Efficiency Analysis With the Behavioral Model

This article presents a 2.4-GHz band 10-W class bridge rectifier that achieves a high-measured efficiency of 90.2%. To clarify the mechanism for obtaining high efficiency, a theoretical analysis with the novel behavioral model of bridge rectifiers is demonstrated. The behavior model includes three functional blocks, namely; 1) impedance transform, which defines the RF impedance for the bridge diode; 2) RF impedance matching; and 3) rectification with the ideal current waveform of the bridge diode. Closed-form formulas for the rectification efficiency and the maximum input power are derived using the behavioral model. The RF impedance can be optimized to obtain high efficiency with the derived formulas, similar to source-pull operations in harmonic balance simulations or experiments. The fundamental limitation on the rectification efficiency is obtained for a bridge rectifier with the optimum RF impedance. In the experimental investigation of the 2.4-GHz 10-W class bridge rectifier, the measured efficiency of 90.2% agreed well with the theoretical value of 91.2% with represented formulas. Furthermore, the derived formulas are applied to the 5.8-GHz 1-W rectifier, and its effectiveness can be confirmed. It is evident that the analyzed efficiencies are close to the fundamental limitations.