W-band energy harvesting rectenna array in 65-nm CMOS

An innovative topology for W-band energy harvesting is proposed using 65-nm CMOS, including an on-chip antenna. The rectifying circuit is based on inverse operation of a differential Colpitts VCO and a loop on-chip antenna is coupled to the rectifying circuit. Occupying total area of 0.611 mm2, the harvester has a peak output power of 0.2 mW with an efficiency of 6%, while the rectifier circuit itself achieved a measured efficiency of 21.5%. Implementing a 3×3 array of CMOS rectennas on a PCB enabled a x3.5 increase in harvested power at 95GHz.