Design and Performance Evaluation of RF Energy Harvester for Wearable Sensor Nodes

In this work, an RF energy harvester to power the wireless sensor nodes, which are embedded with biomedical devices, has been designed. A microstrip antenna with a rectangular patch, inverted U slot in the ground plane, and microstrip fed line is proposed for Wi-Fi frequency band operation. The antenna has an overall size of 54.8 × 49.8 mm ² ; it is designed on the flexible substrate of Polydimethylsiloxane (PDMS), which has a dielectric constant of 2.7. The L-section impedance matching circuit is used for the proposed rectenna in the operating band. The designed rectenna is analyzed and simulated in the CST simulator and achieved the return loss < -40 dB and peak realized gain of 4.42 dB at 2.45 GHz resonating frequency with 65% radio frequency signal to DC signal conversion efficiency with 0 dBm input power. The proposed receiver antenna with designed rectifier circuit is capable to powered low power-sensor nodes and low-power wearable devices.