A Reconfigurable RF Energy Harvesting Front-end Interface for Biomedical Applications

We present in this paper a fully integrated reconfigurable front-end of RF energy harvester. The proposed 8 -stage rectifier can be reconfigured into four stages with Maximum power peak tracking (MPPT) technique, enabling a wide input range of power conversion efficiency (PCE). Based on acquired radio-frequency (RF) power, the proposed front-end can be autonomously reconfigured to provide stable supply voltage for subsequent ultra-low-power circuits. Designed, implemented and simulated in standard 40 nm CMOS process technology, the proposed reconfigurable front-end shows a sensitivity of $\mathbf{- 2 3 d B m}$ for a 1 V output with a $1 \mathrm{M} \Omega$ resistor load. The peak PCE is $\mathbf{4 6. 5 \%}$ at -20 dBm with $1 \mathrm{M} \Omega$ load. Within an input power range of -22 dBm to $\mathbf{4 d B m}$, the output voltage of main power supply path can be maintained between 1 and 1.8 V.