Low Profile MIMO Patch Antenna Design for mmWave 5G V2X with Mutual Coupling Suppression

This paper presents a compact, low-profile multiple-input multiple-output (MIMO) patch antenna designed for millimeter-wave (mmWave) 5G vehicle-to-everything (V2X) communication systems. The antenna operates within the 24–30 GHz range (targeting 28GHz=5G) and integrates a mutual coupling suppression mechanism using defected ground structures (DGS) and electromagnetic bandgap (EBG) elements. The proposed four-element MIMO antenna array, fabricated on a Rogers RT5880 substrate (εr = 2.2, thickness = 0.787 mm), achieves high isolation (>30 dB), high gain (>9 dBi per element), and efficient radiation (>85%) with a compact footprint of 20 × 4.4 mm as overall antenna dimension. The design supports beam steering and polarization diversity, enabling robust performance in dense vehicular environments. The antenna is simulated and verified using Ansys HFSS, and the results are validated through fabrication and measurement.