A Self Threshold Voltage Compensated Rectifier for RF Energy Harvesting using 45nm CMOS Technology

A high frequency rectifier is the core of a RF energy harvesting system. It should offer a very good efficiency at low input power levels and to obtain that compensation of threshold voltage is a very important aspect. A threshold compensation scheme for MOSFETS for RF rectifier applicable in RF energy harvesting system is presented in this paper. The switching of the MOSFET is improved with overall enhancement of output rise time of the system. The design emphasis is to have a simplified circuit without the requirement of any external source so as to achieve self-sustainability in the true sense. The rectifier circuit is derived from the basic Dickson charge pump model and is evaluated using 45nm CMOS process. The design has utilized Metal Oxide Semiconductor Field Effect Transistor instead of basic diodes which ensures low power along with fabrication feasibility. The maximum measured PCE of the design is obtained to be 33% at 4dBm input power level at 500Mhz frequency with 1 Kilo Ohm load resistance. The output transient response rise time has been measured to be 85ns at 500MHz and 50.10ns at 1Ghz.