Low-profile planar rectenna for batteryless RFID sensors

In this paper, a rectenna (i.e., rectifier + antenna), design is proposed and integrated with RFID sensors to harvest ambient power from the RF devices operating in the 2.4 GHz ISM band and convert it to DC. The proposed rectenna combines a two-stage Dickson zero-bias Schottky rectifier circuit with a miniature antenna. Measured performance for the rectifier is given and shown to be 70% efficient in converting RF energy to DC over a wide range of input power.