Low-profile circularly polarized rectifying antenna for wireless power transmission at 5.8 GHz

Portable devices operating without batteries are sometimes desired in wireless applications such as RFID (Radio Frequency Identification) and telemetry. A novel circularly polarized shorted annular ring-slot rectenna (rectifying antenna) on a 0.5 mm thick flexible microwave laminate is proposed for the powering of these devices. Output dc voltage of 1.3 V and axial ratio of 1.5 dB were measured when 32 dBm microwave power was transmitted at 5.8 GHz over a distance of 1 m. Comparing the results with a rectenna designed on a thick rigid laminate, similar performance was observed.