A review: The influence of graphene material integration in antenna characteristics in the presence of bias for fifth and sixth generation wireless communication application

This paper reviews the effect of graphene on antenna characteristics for wireless communication based on fifth generation (5 G) and sixth generation (6 G). The integration method of graphene material on antenna structure in the microwave, millimetre wave, and terahertz bands affects various characteristics. By analysing all the graphene antennas using two types of integration methods:graphene as the only radiating element and graphene-hybrid, different improvements in antenna characteristics are collected, including impedance bandwidth, radiation pattern, antenna gain, antenna efficiency, tuning capability in resonant frequency as well as radiation pattern, reconfigurable capability, and beam scanning capability. This review found that a graphene antenna that implements hybrid integration in antenna structure at 5 G and 6 G frequency bands shows some of these characteristics, such as good tunable resonant frequency, wide impedance bandwidth, gain improvement, mutual coupling reduction, changing of polarisation, direction of main beam, variation of gain, axial ratio, and efficiency when direct current (DC) biasing or resistance is applied and changed. The graphene antenna that uses graphene as the only radiating patch has a moderately biased effect on microwave frequency with respect to the antenna's performance in the terahertz range because of different behaviour of graphene's conductivity, but it also depends on many factors such as frequency, geometry, and specifications. From this review, it appears that the presence of graphene in the antenna will produce better characteristics. It is an opportunity for antennas for future wireless generation by recommending graphene as the hybrid integration method in the antenna structure.