Suppression of Mutual coupling and cross-polarization between Closely Spaced Microstrip MIMO Antennas by using a planar frequency-selective surface structure

This research work presents a novel configuration of frequency-selective structure (FSS) structures aimed at minimizing mutual coupling between the radiating elements whose side by side distance is 0.03λ (1.975mm) where λ is the wavelength in the dielectric medium. The main issue with close spacing MIMO antennas is their high mutual coupling (MC), which negatively impacts their overall performance, leading to degradation in antenna performance. To tackle this challenge, a solution is proposed, inserting a frequency-selective surface (FSS) structure between the antennas, serving as a decoupling mechanism. Periodic structures like FSS can effectively decrease mutual coupling by suppressing the propagation of surface waves within a specific range of frequency. Using the IE3D EM simulator, the antenna parameters were simulated, achieving a remarkable suppression of 14dB in mutual coupling at the resonating frequency of 4.85GHz. The antenna has proven to be suitable for many applications in the area of wireless communication, WLAN (Wireless Local Area Network), and satellite communication systems.