A Novel Methodology to Improve Efficiency and Extend Dynamic Range of Shunt-Diode Class-F Rectifier for Wireless Power Transfer

This paper presents a novel methodology to enhance power conversion efficiency (PCE) and extend dynamic range for class-F shunt-diode rectifier design based on increasing the number of diodes connected in parallel. The prototypes employ class-F harmonic termination which can eliminate almost loss due to harmonic generation and instead of one diode, using more diodes connected in parallel will reduce losses on the diode due to built-in potential voltage (
$V_{bi}$
) and breakdown voltage (
$V_{br}$
). The proposed methodology mechanism is analyzed and demonstrated by closed-form equations where the variation of the losses is clarified in the comparison. Furthermore, based on Schottky diode HSMS2850, two prototypes in two cases: a single diode and two parallel-connected diodes are designed at 0.915 GHz, and measured to compare the efficiency for methodology verification. The implementation results show that the PCE of two parallel-connected diode case is higher than the one of a single diode case when the highest PCEs of two parallel connected diodes are 78.3% in simulation and 73.2% in measurement while the corresponding PCEs of single diode case are only 75.3% and 70.7%. Moreover, the dynamic range of the two-diode prototype is also improved by about 2 dB. These experimental results have good agreement with theory and clarify the advantages of the proposed methodology.