Zelong Hu

Flexible electronic devices are widely used in the Internet of Things, smart home and wearable devices, especially in carriers with irregular curved surfaces. Light weight, flexible and corrosion-resistant carbon-based materials have been extensively investigated in RF electronics. However, the insufficient electrical conductivity limits their further application. In this work, a flexible and low-profile dual-band Vivaldi antenna based on highly conductive graphene-assembled films (GAF) is proposed for 5G Wi-Fi applications. The proposed GAF antenna with the profile of 0.548 mm comprises a split ring resonator and open circuit half wavelength resonator to implement the dual band-notched characteristic. The operating frequency of the flexible GAF antenna covers the Wi-Fi 6e band, 2.4–2.45 GHz and 5.15–7.1 GHz. Different conformal applications are simulated by attaching the antenna to the surface of cylinders with different radii. The measured results show that the working frequency bands and the radiation patterns of the GAF antenna are relatively stable, with a bending angle of 180°. For demonstration of practical application, the GAF antennas are conformed to a commercial router. The spectral power of the GAF antenna router is greater than the copper antenna router, which means a higher signal-to-noise ratio and a longer transmission range can be achieved. All results indicate that the proposed GAF antenna has broad application prospects in next generation Wi-Fi.

With the development of 5G, Internet of Things, and smart home technologies, miniaturized and compact multi-antenna systems and multiple-input multiple-output (MIMO) antenna arrays have attracted increasing attention. Reducing the coupling between antenna elements is essential to improving the performance of such MIMO antenna system. In this work, we proposed a graphene-assembled, as an alternative material rather than metal, film-based MIMO antenna array with high isolation for 5G application. The isolation of the antenna element is improved by a graphene assembly film (GAF) frequency selective surface and isolation strip. It is shown that the GAF antenna element operated at 3.5 GHz has the realized gain of 2.87 dBi. The addition of the decoupling structure improves the isolation of the MIMO antenna array to more than 10 dB and corrects the antenna radiation pattern and operating frequency. The isolation between antenna elements with an interval of 0.4λ is above 25 dB. All experimental results show that the GAF antenna and decoupling structure are efficient devices for 5G mobile communication.