A scheme to improve PCE of differential-drive CMOS rectifier for low RF input power

In this paper, a scheme to improve power conversion efficiency (PCE) of differential-drive CMOS rectifier for low RF input power is proposed. Auxiliary transistors are utilized to provide forward body biasing for the primary transistors of the rectifier. As a result, the threshold voltages of the primary transistors are reduced. Hence, higher PCE is achieved for lower RF input power. The circuits are designed in a standard 180 nm CMOS technology. Measurement results exhibit a considerable PCE improvement by the proposed design at the RF input frequency of 916 MHz in the three-stage configuration. For 50 K$$\mathrm{{\Omega }}$$Ω resistive load, the proposed rectifier has a maximum 10.9 % PCE improvement and requires 2 dB less RF input power to achieve the comparable peak PCE.