Radio-frequency (RF) energy harvesting is a promising technique for powering low-power sensor nodes in environments where battery replacement or wired power deployment is impractical. This study presents the design and comparative evaluation of two single-band rectifiers operating at 2.4 GHz and 5 GHz and one dual-band rectifier covering both frequency bands. The circuits employ HSMS-2850 Schottky diodes in a voltage doubler configuration for RF-to-DC conversion under low RF input power conditions. Compared with the single-band rectifiers, the proposed dual-band configuration achieves enhanced output performance, with an output voltage of 1.65 V, compared with 1.249 V and 0.831 V for the 2.4-GHz and 5-GHz single-band rectifiers, respectively. Furthermore, the dual-band rectifier achieves a maximum PCE of 54.68%, compared with 31.72% and 13.89% for the corresponding single-band designs. These results suggest that dual-band RF-to-DC rectifiers can improve energy harvesting capability in environments where multiple RF frequency bands are available, making them suitable for low-voltage IoT sensor nodes when integrated with appropriate energy storage and power management circuits.

Rectifier circuit, radio frequency energy harvesting, RF-DC