As the core component responsible for capturing radio frequency (RF) energy from the environment, the antenna plays a critical role in determining the overall performance of a RF energy harvesting system. However, existing energy harvesting antennas suffer from limitations, such as single operating frequency bands, low gain, and poor flexibility, which constrain the application of RF energy harvesting systems. In this work, we present a flexible dual-band high-gain antenna array based on graphene-assembled film, fabricated via laser engraving. The antenna achieves stable electrical performance under bending, combining robustness with long service life. By integrating two patch antennas into a shared aperture, it operates efficiently in the 2.32–2.53 and 5.51–5.82 GHz Wi-Fi bands, reaching realized gains of 12.64 and 17.29 dBi, respectively. Leveraging its excellent band coverage and gain performance, the antenna array was implemented in an RF energy harvesting system, and its practical performance was evaluated. The results show that the system is capable of powering various low-power electronic devices. These findings highlight the potential of graphene-assembled film-based antennas for powering Internet of Things devices, and demonstrate their promising application in next-generation RF energy harvesting systems.

In active reconfigurable polarization conversion metasurfaces, the integration of electromagnetic radiation performance and heat dissipation efficiency presents two critical challenges. In this work, we proposed a graphene-based reconfigurable polarization metasurface that integrates heat dissipation and electromagnetic regulation functions. The proposed graphene metasurface modulates the polarization state of the reflected wave at multiple frequency bands via the on-off switching of PIN diodes. When the PIN diode is in the ON state, the metaurface can modulate the incident linear polarization wave into its cross-polarization wave in 5.73–6.15 and 11.25–13.10 GHz, and into a circular polarization wave in 6.27–10.18 GHz. When the PIN diode is switched to the off state, the cross-polarization transitions are achieved in 5.75–7.32 and 12.83–14.24 GHz, with full reflection in the band of 7.92–10.15 GHz, and circular polarization in 12.83–14.24 GHz. In addition, when the graphene metasurface system worked after a long period of operation, the temperature of the graphene metasurface is 21.3 °C, which is 34.2 °C lower than that of the copper metasurface, this has less impact on the temperature drift effect of the PIN diode. The integrated graphene polarized reconfigurable metasurface for radiation and heat dissipation addresses the performance, volume, and thermal management limitations of traditional systems through multifunctional integration and dynamic tunability, offering significant potential for future smart electromagnetic devices application in communication, radar, and Internet of Things.

Herein, we report the design, fabrication, and performance of two wireless energy harvesting devices based on highly flexible graphene macroscopic films (FGMFs). We first demonstrate that benefiting from the high conductivity of up to 1 × 10⁶ S m⁻¹ and good resistive stability of FGMFs even under extensive bending, the FGMFs-based rectifying circuit (GRC) exhibits good flexibility and RF-to-DC efficiency of 53% at 2.1 GHz. Moreover, we further expand the application of FGMFs to a flexible wideband monopole rectenna and a 2.45 GHz wearable rectenna for harvesting wireless energy. The wideband rectenna at various bending conditions produces a maximum conversion efficiency of 52%, 46%, and 44% at the 5th Generation (5G) 2.1 GHz, Industrial Long-Term Evolution (LTE) 2.3 GHz, and Scientific Medical (ISM) 2.45 GHz, respectively. A 2.45 GHz GRC is optimized and integrated with an AMC-backed wearable antenna. The proposed 2.45 GHz wearable rectenna shows a maximum conversion efficiency of 55.7%. All the results indicate that the highly flexible graphene-film-based rectennas have great potential as a wireless power supplier for smart Internet of Things (IoT) applications.