Multiband plasmonic MIMO antenna array for 6G communications

This paper presents the design and investigation of a two-element MIMO antenna using a series-fed microstrip antenna array for next-generation (Next-gen) communications in the THz regime. The antenna array is developed on an ultra-thin substrate material with graphene patterning to obtain quad-band radiation. Concentric split rings of various radii are used in the development of each element and three sections are used to construct each of the series-fed antenna array within a footprint of 50 × 16 μm. The series-fed configuration is chosen to maximize the antenna radiation making it suitable for low-power applications. The proposed series-fed antenna works at 3.4, 3.6, 4.96 and 5.6 THz with a return loss greater than 25 dB. The estimated bandwidth of the series-fed antenna array is 128, 142, 145 and 176 GHz making it suitable for high-speed data communication. The peak simulated gain is greater than 6 dBi while the total efficiency is above 80% in the four operating bands. Further, to enhance the antenna performance for a highly cluttered environment, a two-element Multiple-Input Multiple-Output (MIMO) array is constructed with an element spacing of 22 μm with an inherent isolation of 20 dB. The MIMO performance parameters are evaluated and presented.