A Low Power Backscattering Architecture for Batteryless Sensor Nodes

This paper presents a novel architecture for low power IoT sensor nodes, integrating backscattering and energy harvesting circuits. The proposed circuit employs a bandpass filter (BPF) integrated with an efficient wide-band rectifier and a variable impedance to create two distinct and nearby frequency bands for energy harvesting (fEH) and backscattering (fBS). For a two-tone incident signal with a total peak power of -7 dBm, -16.7 dBm power is backscattered while 56.45 μW power is harvested. Backscattering achieves 10.1 dB dynamic range with 8% reduction in the efficiency of the energy harvester. Integrated backscattering and harvesting circuit (IBHC) achieves 45% peak power conversion efficiency (PCE) at -10 dBm and 10 MHz minimum frequency spacing between the two bands.