A 433-MHz Compact Inverse Class-F Rectifier for Biomedical Wireless Power Transmission

This letter presents a novel implementation of inverse class-F (class-F ^{-1} ) rectifier based on lumped elements for biomedical wireless power transfer (WPT) at 433 MHz. Specifically, in order to reshape the diode current and voltage according to the class-F ^{-1} waveform, a parallel LC resonator is deployed at the diode anode as a band-stop filter to provide infinite impedance for the second harmonic. Meanwhile, the third harmonic is terminated with zero impedance by a series LC network at the diode cathode side where its quality factor is also controlled to facilitate the fundamental matching. A prototype is fabricated and measured for verification showing that the peak power conversion efficiency (PCE) is achieved at 72.8\% with an input power of 5 dBm. Also, the proposed rectifier exhibits \text{PCE}>50\% within a wide dynamic range of 22.5 dB and a compact size of 13\times7 mm ^{2} , which indicates an advantageous performance over the other existing designs with similar diode and frequency.