Compact, gain-enhanced 5G mmWave antenna with metallic ground-backed reflector for high-speed railway communication systems

This research presents a compact, high-gain millimetre-wave antenna tailored for reliable 5 G communication in high-speed railway environments. The proposed antenna supports dual-band operation at 28 GHz (n257/n258) and 38 GHz (n260), enabling robust vehicle-to-infrastructure (V2I) links required for next-generation railway systems. The radiator occupies only 12 × 8 mm² on a Rogers 6010LM substrate (εᵣ = 10.2, h = 0.64 mm). A metallic ground-backed (MGB) reflector, positioned 9 mm behind the patch—λ/4 at 28 GHz—enhances forward radiation, suppresses back-lobes, and ensures highly directional coverage along railway tracks. The antenna achieves measured peak gains of 7.96 dBi at 28 GHz and 8.20 dBi at 38 GHz, with excellent impedance matching and stable radiation patterns under mobility scenarios. Its unique combination of compact footprint, reflector-aided gain enhancement, and stable dual-band performance under dynamic conditions distinguishes it from conventional mmWave solutions, making it a strong candidate for 5G-based high-speed railway communication modules and arrays. • Compact dual-band mmWave antenna 10 × 8 mm² designed for 28 GHz and 38 GHz 5 G high-speed railway communication systems • Metallic ground-backed (MGB) reflector enhances forward gain and suppresses back-lobes for reliable vehicle-to-infrastructure (V2I) links • Measured peak gains of 7.96 dBi at 28 GHz and 8.20 dBi at 38 GHz with excellent impedance matching and stable radiation patterns • Lightweight and low-profile solution suitable for integration into compact 5 G railway communication modules and phased-array systems