High isolation quad ports MIMO antenna loaded with FSS for 5G communication

This paper introduces a high isolation quad ports MIMO (Multiple-Input Multiple-Output) antenna with a frequency selective surface (FSS) structure for higher frequency bands in 5G communication systems. The recommended antenna is designed for 28 GHz application. The single unit of the antenna consists of a microstrip feed line on one side and a rectangular slot in the ground plane on the other side. The four MIMO antennas are arranged orthogonally on a Rogers RO4003C substrate with a permittivity of 3.38, a loss tangent (tan δ) of 0.002, and a height of 0.203 mm. The substrate features a cross-shaped cut to enhance the isolation between ports. An FSS is placed beneath the MIMO system to improve the overall gain across the desired frequency band. The antenna size is 25.7 × 25.7 mm². The design and simulation of the proposed structure were carried out using CST MW Studio. The antenna with and without the FSS structure was constructed and tested to verify the simulation results. The results indicate that the suggested structure is worked from 25.5 GHz up to 30 GHz with insertion loss ≤ -22 dB and peak gain of around 8dBi. As well, the envelope correlation coefficient (ECC), diversity gain (DG), and channel capacity loss (CCL) are measured and achieved ≤ 0.002, ≥ 9.99 dB, ≤ 0.2 bit/s/Hz, respectively. Also, extra MIMO parameters such as mean effective gain (MEG), channel capacity, and total active reflection coefficient (TARC) are extracted and achieve good outcomes confirming the ability of the antenna to be applicable for 5G networks.