A planar, low profile and lightweight rectenna was designed
and tested for power harvesting at the 2.45 GHz ISM
band. The rectenna structure was formed using a two-stage
Dickson charge pump voltage-doubler with a miniature 2nd
iteration Koch antenna. The proposed rectenna achieved a
comparatively high realized gain (4 dBi) and good RF to DC
conversion efficiency (up to 70%). With these specifications,
the rectifier harvested enough energy to turn on a 1.6V LED
from 3.1 meters and to turn on a commercial RFID sensor from
2.1 meters using a commercial RFID reader for excitation (4W
EIRP at 2.45 GHz ISM band). Further improvements to the
power harvesting circuit can still be achieved using multiple
antenna and more efficient diodes. At the conference, we will
discuss these improvements along with other issues such as
DC-DC conversion, power management, antenna bandwidth,
antenna size and diode rectification efficiency.