Design of 900 Mhz AC to DC Converter Using Native Cmos Device of TSMC 0.18 Micron Technology for RF Energy Harvest Application

Abstract

RF signal carries very low amount of energy and can be easily dissipated as heat loss. Threshold voltage and leakage current that are inherent in MOS transistors significantly affect the performance of an RF AC to DC converter. A device with bulk connected to its drain improves the threshold voltage and leakage current. This work designs the half-wave and full-wave AC to DC converters with devices' bulk connected to source and devices' bulk connected to drain. The designs used the native devices in TSMC 0.18 micron CMOS technology, and were simulated using transient analysis in different process corners and operating temperatures. In simulations, the RF signal was represented by a sinusoidal input of 900 MHz frequency and of 390 mV amplitude. The sizes of transistors and the number of stages, of each converter, that resulted to highest power efficiency were determined via circuit simulations. The optimal design was a four-stage half-wave AC to DC converter with devices' bulk connected to drain, which produced a DC output of 2.7 V with 37.42 % efficiency at 100 kilo ohm load.