A Compact Rectifier Design Method Utilizing Harmonics

This paper proposes a compact rectifier design method for utilizing harmonics. Based on total reflection generated by pure reactance loads at the second harmonic (2nd) and open circuit at the third harmonic (3rd), a compact DC-pass filter is designed to effectively utilize the 2nd and 3rd harmonics excited by the rectifying diode. The amplitudes of the harmonics can be controlled by adjusting the input impedances of the DC-pass filter at harmonics. A prototype operating at 5.8 GHz fundamental frequency is implemented and measured to validate the scenario. When the input power is 18.3 dBm, the measured rectifying efficiency is 71.3%, while the 2nd and the 3rd harmonic amplitudes are −2.4 dBm and 0.1 dBm respectively. This method could also be extended to design a rectifier only utilizing the 2nd or the 3rd harmonic.