Efficient Multi-Band Energy Harvesting Circuit for Wireless Sensor Nodes

In this paper, we present a simple, yet efficient, Multi-Band RF energy Harvesting (MB-RFH) circuit. The circuit overall dimension is (115 x 52 x 1.6) mm(3) including the storage capacitor and operates over quad-band RF frequencies. Unlike the related works which use a separate antenna and a separate matching circuit per frequency band, we propose to use a single antenna and a single matching circuit that can operate over the different frequencies of interest. We design a single antenna that is optimized to simultaneously operate at 900 MHz, 1.8 GHz, 2.1 GHz, and 2.4 GHz with directivity of 2.119, 4.256, 4.436 and 4.028 dBi, respectively. The overall RF-to-DC conversion efficiency is 85.7% at -10 dBm, 52.3% at -15 dBm, and 23.8% at -20 dBm, respectively. Thus, our MB-RFH circuit is suitable for typical wireless sensor network (WSN) nodes.