A 94 GHz Voltage-Boosted Energy Harvester in 45 nm CMOS Achieving a Peak Efficiency of 21.2% at -8.5 dBm Input Power

This paper presents a comparative study of four different rectifier topologies at 94 GHz in 45 nm CMOS. The effect of voltage boosting on the Power Conversion Efficiency (PCE) is explored. Among the compared topologies is a novel architecture proposal, the inverted cross-coupled oscillator. This rectifier reaches a maximum PCE of 30.7 % at an input power of -5dBm. Boosting this rectifier with a supporting cross-coupled 4-transistor cell has a significant influence on the low-power efficiency, resulting in a maximum PCE of 21.2 % at only -8.5dBm input power. To the authors’ knowledge, these are the highest reported efficiencies in CMOS at this frequency.