High-Efficiency Millimeter-Wave CMOS Switching Rectifiers: Theory and Implementation

This article proposes the concept of millimeterwave (mm-wave) switching rectifiers originated from drainpumped mixers. The topology and circuit design methodology are distinctly different from other CMOS mm-wave rectifiers which adopt voltage multiplier techniques. Operation principle and RF-to-dc power conversion efficiency (PCE) of the proposed switching rectifiers are analyzed to overcome the fundamental limits on achievable performance of switching rectifiers at mm wave. In order to demonstrate the utility of the proposed concept, two prototypes in 65-nm bulk CMOS technology have been implemented: two fully integrated switching rectifiers operating at Ka-band and W-band. A peak PCE of 36.5% at 35 GHz with a load resistance of 50 Ω at about 15-dBm input power is measured for the Ka-band rectifier. Measurement results for the W-band rectifier also indicate that the PCE peaks at 27% at 91 GHz for a load resistance of 43 Ω at about 16-dBm input power. To the best of our knowledge, the two fully integrated rectifiers which occupy the smallest chip area exhibit a competitive PCE reported among Ka-band and W-band CMOS rectifiers, competing well with GaAs counterparts where the Schottky diode is available.