Mutual Coupling Reduction between two SIW Antennas by Using Isolation Wall

Abstract

This paper focuses on two-element MIMO antenna system based on Substrate Integrated Waveguide (SIW) structure. The proposed antenna configuration operates at the central frequency of 5.86 GHz dedicated for Sub-6 GHz 5G communication applications. The design includes 30 metallic vias drilled on Preperm L960HF substrate. The operating frequency can be adjusted by changing the diameter sizes of the SIW antenna holes. The appropriate frequency band was obtained by performing parametric studies on hole sizes. Vertical metal Wall with 60 mm length and 10 mm width is mounted between the closely placed SIW antennas to suppress the mutual coupling. The presented MIMO antenna is excited with a 2.6 mm width feed line having 50 Ω characteristics matched impedance. With the added isolation wall, the S21 insertion loss was reduced from -18 dB to -28 dB without any significant change in the resonance frequency. In addition, the peak gain improved from 6.32 dBi to 7 dBi at 5.5 GHz.