Wide-band and Efficiency-Improved 0.18um CMOS RF Differential Rectifier for Wireless Energy Harvesting

Wireless energy harvesting has promised to completely change the conventional wired technology for powering the wireless sensor nodes. In the current study, we introduce a high efficient, wideband, and compact RF rectifier for batteryless wireless communication applications. We propose an improved energy harvester which maximizes the efficiency over a wide input frequency range. The proposed design relies on integrating a differential broadband matching circuit with a CMOS rectifier. In order to maximize the operational bandwidth of the cross coupled CMOS rectifier architecture, T-Matching circuit composed of inductive and capacitive elements is suggested. The rectifier along with the matching circuit is fabricated using the standard 180-nm CMOS technology. The measurements of the proposed design were verified against the simulation results. The functionality of the rectifier design, which operates from 1.8 to 4.2 GHz, is studied through simulation in Agilent, ADS and implementation using Cadence, Virtuoso. The simulation and measurement results reveal that the harvester could provide a 2.1 VDC with 5 dBm input power and the efficiency is maintained above 30% over the frequency band of interest. The peak efficiency obtained from the rectifier architecture is 51 % at excitation frequency 2.6 GHz, input power 5 dBm and a terminal load of 3.5 k Ω.