The demand of a long life battery unit to supply the power for wireless application devices show significant grows. The radio frequency is one of the sources that can harvest the surrounding energy to a desired voltage due to availability to find everywhere with free cost. This paper presents a design of RF to DC conversion circuit for energy harvesting. The proposed circuit consists of rectifier, ring oscillator, charge pump and regulator is implemented in 0.13?μm CMOS technology. The rectifier is rectified the RF input signal to a DC voltage. The combination of charge pump and the ring oscillator act as a DC to DC converter to boost a low input voltage to higher output voltage. Finally the DC output voltage will be regulated to a desired 1.2?V DC. The simulations result shows that the RF signal of 900?MHz to 2400?MHz, -16.48?dBm is converted to DC regulated voltage of 1.25?V DC at 50?kΩ load.
