A 918MHz Wide-Range CMOS Rectifier with Diode-Feeding and Switch-Capacitor-Based Load Modulation Technique

Abstract

This paper presents a wide-input-range rectifier design with a diode-feeding (DF) architecture and load modulation. Dynamically-biased diodes are connected to the gates of the rectifying transistors to create bias voltage differences for PMOS and NMOS devices and the isolation of the reverse currents at different input power levels. Also, the switch-capacitor-based load modulation scheme is proposed to achieve optimal efficiency over wide-range load current deviations automatically. The proposed four-stage rectifier design was fabricated using 65nm CMOS technology and occupies a silicon area of 0.92 x 0.27mm(2). The measured sensitivity of the rectifier is -15dBm at 1M Omega load, and the peak power conversion efficiency is 28% at a load of 22k Omega With the load modulation scheme, the conversion efficiency is enhanced by >10% in a load current from 7 mu A to 35 mu A, when compared to a design without the load modulation scheme.