Mafa, Ike MWinberg, SFerreira, Riaan2026-10-052026-10-052026-05979-8-3315-6022-52375-531810.1109/RadarConf2663773.2026.11674989http://hdl.handle.net/10204/14971This paper presents a compact dual-polarized stacked microstrip patch antenna designed for C-band spaceborne and UAV-mounted Synthetic Aperture Radar (SAR) systems operating in the ITU-allocated 5.25–5.57 GHz band (320 MHz). The antenna employs a novel coupling-excited feed architecture in which two orthogonal coaxial probes excite inverted U-shaped slots etched into a driven patch, enabling strong coupling and improved impedance shaping. A parasitic patch—scaled 5% smaller than the driven patch and incorporating matching rounded corners—is placed above the radiator to form a vertically coupled two-resonator system that broadens the impedance bandwidth while preserving planar symmetry suitable for array integration. Electromagnetic simulations performed in Altair FEKO demonstrate a −8 dB impedance bandwidth of 5.32–5.78 GHz (≈480 MHz), fully covering the 320 MHz SAR allocation. The antenna maintains inter-port isolation better than −17 dB across the band, with a peak isolation of −24.3 dB at 5.55 GHz; such isolation levels significantly reduce crosstalk in dual-polarized SAR channels, improving polarimetric accuracy without requiring external decoupling networks. The realized gain remains stable between 3–5.3 dBi, and cross-polarization levels stay below −18 dB in the main beam region. These results confirm that the proposed architecture offers a compact, low-profile, and wideband dualpolarized radiator well suited for next-generation space-borne and UAV SAR front ends.AbstractenDual-polarized antennasStacked microstrip patchU-slot feedParasitic couplingC-bandSynthetic Aperture RadarSARWideband antennasUAV radar sensorsConference PresentationN/A