High frequency rectifier for RF energy harvesting systems

Wireless communication systems are widely used in our daily lives, thus the power density of ambient radio frequency (RF) energy highly increased accordingly. Therefore, the energy harvesting system can be applied to recycle the energy to use with small devices such as sensor devices which consume only a small amount of energy. Furthermore, the application can be modified to use with wireless chargers and power detectors. The system consists of a rectifier circuit and an antenna. The RF energy is harvested by the antenna and the received RF signal is converted to be direct current (DC) power by rectifier circuit, thus the performance of the system will depend on the quality of the antenna and the efficiency of the rectifier circuit. The high efficiency rectifier can be achieved by the low power dissipation in the diode and the optimal impedance of the matching between the receiving antenna and the rectifier circuit. This paper proposes the source-pull simulation to determine the optimal impedance matching for the rectifier that can provide 35.53% of the maximum efficiency with 1.09 V of the DC output voltages and 3.16 mA of the DC load currents at 10 dBm of the input power by 2.42 GHz of continuous wave signal. At 2.1 GHz, the circuit can provide 26.41% of the efficiency with 0.939 V of the DC output voltages and 2.75 mA of the DC load currents at 10 dBm of the input power. For the broadband performance the circuit can provide the efficiency higher than 27% from 2.4 GHz to 2.5 GHz of the operation frequency and the efficiency more than 25% for the frequency from 2.1 GHz to 2.2 GHz at 10 dBm of the input power.