Miniaturized multi-band triple mode dual polarization MIMO antenna for vehicular communication

This article proposes a novel, low-profile, multi-band, dual-polarized, semi-flexible leaky wave MIMO antenna designed for vehicular communication systems. The antenna features two periodic Spoof Surface Plasmon Polariton Transmission Lines (SSPP-TLs) and periodic rectangular strip patches, parasitically fed via orthogonal ports, enabling efficient multi-directional radiation. To optimize performance, a defected ground structure (DGS) and complementary elliptical split-ring resonators (CESRRs) are integrated into the back layer, with nested CESRRs added to an extra layer to enhance radiation characteristics and minimize back and bidirectional emissions caused by an incomplete ground plane. A meander line neutralization network also connects the ports to improve isolation and enable a third radiation mode. The compact antenna, with dimensions of 13 × 11 × 0.25 mm³, demonstrates excellent impedance matching (S11<−15.34 dB), high directive gains (up to 11.5 dBi), dual-polarization, high isolation (>23 dB), and robust MIMO performance metrics, including Channel Capacity Loss (CCL<3), Diversity Gain (DG>9.85), Envelope Correlation Coefficient (ECC<0.01), and Axial Ratio (AR<2.5). On-vehicle testing across various positions confirmed the antenna's adaptability for different vehicular communication scenarios (V2V, V2P, V2I) by facilitating communication with vehicles, pedestrians, roadside units, and mobile networks. The Specific Absorption Rate (SAR) was analyzed to ensure safety for drivers and pedestrians, with simulation and measurement results aligning closely. The proposed antenna offers superior reliability, adaptability, and safety for vehicular communication systems by integrating advanced resonator technologies and leveraging robust MIMO design. Its compact size and high performance make it an ideal candidate for modern automotive setups, addressing key challenges in connected and autonomous vehicle networks.