Compact Quarter-Mode SIW MIMO Antennas Using Neutralization Line for V2X Applications

We introduce a neutralization line (NL) in quarter-mode substrate-integrated waveguide (SIW) antennas, aimed at constructing compact MIMO antennas for V2X applications while mitigating their mutual coupling. By exploring a simple NL between dual-element quarter-mode SIW antennas, it is discovered that mutual coupling can be effectively suppressed even though the edge-to-edge distance is only 1 mm. The effectiveness and adaptability of the NL in decoupling SIW MIMO antennas are confirmed. Meanwhile, it is revealed that the proposed MIMO SIW antennas with NL has advantages of high isolation, compactness, and easy integration.