Flexible slot-ring antenna for RF wireless energy harvesting

In this paper, a flexible slot-ring antenna printed on polyethylene terephthalate (PET) substrate is designed for wireless power harvesting at 2.4 GHz. The main aim of this work is to design, fabricate and measure the energy harvesting performance of this PET-based antenna. We have evaluated a feasible new and energy-efficient method for patterning copper layer on PET substrate by E-beam evaporation, without resorting to the etching process in conventional metal patterning. The thickness of copper layer is controllable, and in this case it is 150 nm. The antenna manufactured by this method is flexible and exhibits good performance. The proposed antenna is characterized by vector network analyzer (VNA) and microwave anechoic chamber. The reflection coefficient is −26.4 dB at 2.4 GHz, and the measured radiation gain is 2.7 dBi at 2.45 GHz.