5G MIMO Antenna: Compact Design at 28/38 GHz with Metamaterial and SAR Analysis for Mobile Phones

Meeting the challenge of preserving the compact form of 5G smartphones while accommodating millimeter -wave (mm -wave) bands with a substantial frequency difference, we have introduced an ultra -compact 4 -port dual -band multiple -input, multiple -output (MIMO) antenna. This innovative design utilizes a metamaterial-inspired electromagnetic bandgap (EBG) structure to minimize mutual coupling (MC) effectively across a wide frequency range. Constructed on a Rogers TMM4 substrate, the antenna has overall dimensions of 17.76 x 17.76 mm(2). It incorporates four planar patch antennas placed at the corners, arranged perpendicularly. Each antenna element is optimized for dual -band operation at 28/38 GHz, featuring a rectangular patch with four slots and a full ground plane. The gap between patches measures 0.5 lambda o, and the EBG ensures efficient and cost-effective reduction of mutual coupling among the MIMO antenna elements. Specific absorption rate (SAR) analysis validates the suitability of this MIMO antenna for 5G mobile phones operating within the targeted frequency band.