Reducing Mutual Coupling of Closely Space Microstrip Antennas for MIMO Application at 5.8 GHZ

Abstract

An efficient mutual coupling reduction method is introduced in this paper for an extremely closely-spaced dual-element microstrip antennas positioned on a finite sized ground plane for MIMO application at 5.8 GHz. High isolation can be achieved through a simple transmission connection line (TNL) between the microstrip antennas. The position, length, and line width of the transmission connection line need optimize designing to maximize the isolation. It is found that isolations of more than 48 dB can be achieved between two parallel microstrip antennas sharing a common ground plane, with inter-antenna spacing of 0.038λ ₀ and ground plane size 0.85λ ₀ × 0.735λ ₀. All along this paper, several prototypes are fabricated and their performances measured to validate the obtained IE3D moment method-based simulation results.