[This article belongs to Volume - 39, Issue - 04]

Reflectarray Antennas for 5G Communications: A Comprehensive Review

The need for higher data transmission speeds in various applications is driving the need for broader operational frequency ranges in upcoming 5G/6G communication systems. Consequently, this imposes stringent requirements for the development of appropriate antennas. Reflectarrays (RAs) are being considered as promising options for supporting 5G/6G systems because of their many benefits, including as high gain, beam shaping, beam scanning, reconfigurability, and multi-beam features. Nevertheless, the poor efficiency of reflectarrays is attributed to their narrowband nature. This work comprehensively investigates the present condition of wideband reflectarrays. Wideband reflectarrays are evaluated and categorized according to four wideband phase tuning techniques. The bandwidth is evaluated and contrasted from both a unit cell and reflectarray system standpoint, with a specific emphasis on the gain-bandwidth performance. The text discusses several unit cell geometries that are capable of wideband operation. These geometries are categorized based on the technique used for wideband phase tuning. Then, taking into account variables like operating frequency, reflection phase range, substrate structure and material, aperture size, aperture efficiency, focal distance, cross-polarization performance, gain, and side lobe levels, we examine the effect of each wideband phase tuning method on the gain-bandwidth performance of reflectarrays. In conclusion, the various methods of phase tuning are compared and contrasted, and recommendations are given for the construction of reflectarrays with a broad gain-bandwidth.