A Class-C CMOS Rectifier With Active Modulation Achieving >76% Peak Efficiency and Extended Input Power Range Over 8.8 dB Across Multiple Frequency Bands

This paper presents a class-C cross-coupled differential CMOS rectifier with an active modulation technique enabled by dual-path feedback loops. The proposed design effectively mitigates reverse leakage current losses at high input power levels, thereby enhancing power conversion efficiency (PCE) and extending the input power range (IPR). Unlike conventional designs that employ resistive or diode-based feedback control circuits in the DC path, leading to degraded PCE at high RF power levels and additional power consumption in the feedback loop, the proposed scheme incorporates a fully active modulation mechanism that improves PCE across a wide frequency range. Fabricated in a standard 180 nm CMOS process, the rectifier occupies a compact active area of 0.009 mm <tex-math notation="LaTeX">²</tex-math> . Measured at a 100 k <tex-math notation="LaTeX">Ω</tex-math> load, the design achieves a peak PCE greater than 76%, an IPR (PCE >60%) spanning over 8.8 dB, and a sensitivity better than -18 dBm for generating a 1 V output consistently at 433 MHz, 920 MHz, and 2.4 GHz operating frequencies.