High Isolation and High Gain of MIMO Antennas With FSS for 5G mm‐wave Applications

ABSTRACT This paper presents a comprehensive study on the gain enhancement and higher Isolation of a 28 GHz MIMO antenna system for 5 G communications using Frequency Selective Surfaces (FSS). The antenna under study is designed with dimensions of 2.86λ × 2.86λ × 0.047λ; the ground patches have a dimension of 7.6 × 11 mm 2 , the substrate is a Rogers RT885 (εr = 2.2, height = 0.51 mm), and operating at 28 GHz. A 4‐element MIMO antenna array is formed by orthogonally placed elements in order to optimise spatial diversity. To improve isolation between the antenna elements, a mutual coupling reduction technique is employed. Furthermore, a 36‐element FSS array is strategically placed above the MIMO antenna to significantly boost the gain. The initial gain performance without the FSS is 4.2 dBi at 28 GHz, by placing the FSS surface 7 mm above the MIMO antenna, this increases the gain to 8.4 dBi, resulting in a gain enhancement of approximately 3.6 dBi. Simulation results, obtained using CST Microwave Studio, demonstrate notable improvements in the antenna gain. The integration of FSS proved to be an effective solution for meeting the stringent performance requirements of 5 G communication systems, particularly in high‐frequency mmWave applications. The present work aims to enhance gain, get high efficiency, improve the isolation between the ports, good value of ECC.