Frequency Division Duplex-Multitone Approach for Backscatter Aided SWIPT

This paper presents a combined simultaneous wireless information and power transfer (SWIPT)/third-order intermodulation (IM3) backscattering architecture. The self-interference signal degrades the reliability and reading range in the base station. An active IM3 backscatterer has been employed to improve the signal-to-noise ratio and reduce self-interference in the base station. In addition, we have shown both analytically and experimentally that the proposed frequency modulated signal improves SWIPT performance. Finally, a joint operation with frequency modulated downlink, 10.1 dB IM3 backscattering dynamic range, and 25.5% power conversion efficiency is demonstrated when the sensor node consumes $7.94 \mu \text{W}$ RF power.