A Dual-Polarized PIFA Array with CM/DM Excitations for Low-Coupling Airborne Applications

This paper presents a low-profile dual-polarized PIFA MIMO array for 4.9-GHz airborne ATG communications. The design exploits CM/DM excitations for dual polarization and self-decoupling, while inter-element slots are introduced to suppress array-level coupling on the shared ground plane. In addition, a reflector is incorporated to emulate the metallic fuselage environment and suppress backward radiation. Simulations show that the proposed array operates over 4.85-4.95 GHz, improves S21 from about -10 dB to -18 dB, and increases the forward realized gain to 7.8 dB while reducing the backward realized gain below -18 dB under DM excitation. The proposed structure is therefore promising for compact airborne Sub-6 GHz array integration.