Harmonic-Recycling Rectification Based on Novel Compact Dual-Band Resonator

TL;DR

This paper introduces a novel compact dual-band resonator that suppresses harmonic generation in RF-dc conversion, improving efficiency and simplifying circuit design.

Contribution

The paper proposes a new dual-band resonator design that eliminates the need for traditional harmonic filters, enhancing performance and reducing circuit complexity.

Findings

Harmonic suppression improved by 18.4 dB (second harmonic) and 7.6 dB (third harmonic).

Power conversion efficiency increased to 73.2% at 10 dBm RF power.

Validated through fabrication and testing at 2.2 GHz.

Abstract

Harmonic generation during radio frequency (RF)-dc conversion causes performance degradation of a microwave rectifying circuit. To suppress and recycle the harmonic power, this letter proposes a novel compact dual-band resonator (DBR) based on a microstrip coupled transmission line. It presents open-circuits at the second and third harmonic frequencies, which effectively block the higher order harmonic for power recycling. The conventional input cascading filters for harmonic rejection can be eliminated, simplifying the circuit topology and reducing loss. Theoretical analyses were carried out and corresponding equations were formulated for the proposed DBR. For validation, two rectifying circuits with/without the DBR operating at 2.2 GHz were fabricated and tested. Using the proposed DBR at 10 dBm RF power, the suppression of the second and third harmonic powers is enhanced by 18.4 and 7.6 dB, respectively. Besides, an improvement of RF-dc power conversion efficiency (PCE) was observed; specifically, PCE reached 73.2% at 10 dBm compared to 71.6% obtained from an equivalent rectifier.