Reconfigurable Multiband RF Energy Harvesting System in CMOS for Adaptive Power Efficiency

This paper presents the design and implementation of a reconfigurable, fully integrated multiband Radio Frequency Energy Harvesting (RFEH) system in CMOS technology. The proposed architecture dynamically selects the frequency band with the highest ambient power density, thereby optimizing power conversion efficiency (PCE) for low-power applications such as the Internet of Things (IoT). While conventional RFEH systems rely on single-band designs or offchip multiband systems, they face significant limitations in adaptability and compactness, often resulting in reduced efficiency in real-world RF environments. Our design incorporates an on-chip tunable impedance matching network and a control circuit that manages frequency switching between 0.96 GHz and 1.8 GHz, targeting both compact integration and adaptability. Simulation results demonstrate that the system achieves a peak PCE of $\mathbf{3 8. 3 4 \%}$ across a dynamic range of 22 dB. The fully integrated architecture, occupying $900 \mu \mathrm{~m} \times$ $820 \mu \mathrm{~m}$, provides a viable solution for high-efficiency, small-form-factor energy harvesting systems.