Flexible Hybrid Solar/EM Energy Harvester for Autonomous Sensors
A flexible ElectroMagnetic (EM)/solar energy harvester is proposed that finds application in low power energy autonomous wireless sensor networks and RFID-enabled sensors. A low cost, compact and conformal harvester is implemented on a flexible polyester (PET) substrate combining a rectenna for EM harvesting and a flexible amorphous silicon solar cell for solar energy harvesting. A compact design is achieved by placing the solar cell on top of the radiating element. A coplanar UWB monopole antenna is designed and a rectifying network is optimized using harmonic balance in order to maximize the rectenna efficiency for low power electromagnetic signals in the GSM-850 and GSM-1900 frequency bands.