Metamaterial-based absorber and voltage rectifier circuit in ISM band for wireless power transmission in IoT applications

The proposed study in this article involves two structures: a polarization-independent high-absorption metamaterial-based absorber and a voltage doubler rectifier circuit. Based on the simulated results of the designed metamaterial-based absorber, the reflection coefficient at 2.4 GHz is −28 dB and the absorption is 99%. The designed absorber structure is fabricated and a measurement result is obtained. A voltage doubler rectifier circuit is designed to convert the radiofrequency (RF) energy absorbed by the metamaterial-based absorber into direct current (DC) energy in the 2.4 GHz frequency band; simulation and measurement results are obtained. The proposed rectifier achieves 58.7% RF–DC conversion efficiency and a 1.54 V output at 2.4 GHz with a 5 dBm input power. The present study aims to convert the harvested RF energy into electrical energy with high efficiency in a voltage doubler rectifier circuit using a smaller-size, easy-to-design metamaterial absorber for Internet of Things (IoT) devices.