Türk Doğa ve Fen Dergisi, cilt.9, sa.2, ss.148-151, 2020 (Hakemli Dergi)
In MIMO antennas, mutual coupling that adversely effects antenna performance is due to
the surface currents. To date, many techniques such as Electromagnetic Band Gap (EBG) structures,
metamaterial unit cell, band-stop filters and Frequency Selective Surfaces (FSS) have been
proposed to suppress these surface currents. FSSs, when properly designed, can act as a band-stop
filter in a given frequency range and thus prevent the propagation of these surface waves in the
microstrip patch arrays. In this study, a new FSS unit cell is designed to reduce the mutual coupling
effect caused by surface currents between two identical 2x1 patch antenna arrays with a 3.49 GHz
operating frequency. These designed FSS unit cells are placed between the patches with a 1x5
periodic sequence. According to the simulation results, mutual coupling effect decreased by 26.6 dB
without any shift in the transmission band with only 0.48 dB change in S11. Finally, Envelope
Correlation Coefficient-ECC curves are plotted separately for the antenna array with and without
the FSS wall. It is observed that the ECC of the antenna array is dropped from 0.16 to 0.07 by
applying the proposed isolation wall.