Abstract: A high-isolation dual-polarized microstrip antenna featuring a multi-level decoupling strategy is proposed for X-band applications. To enhance bandwidth and suppression, a hybrid multilayer architecture with an air gap is employed. The design integrates non-contact T-shaped feeds, orthogonal dual H-shaped slots, and substrate integrated waveguide(SIW) based virtual electric walls. These features collaboratively eliminate direct conduction paths, exploit magnetic current orthogonality, and block substrate mode propagation. Measured results validate that the effective impedance bandwidths (S₁₁/S₂₂ < –10 dB) are 9.15–10.83 GHz and 8.98–10.71 GHz. The voltage standing wave ratio(VSWR) remains better than 1.5 within 9.43–10.07 GHz and 9.40–10.16 GHz. The antenna exhibits a stable peak gain of 8.9 dBi, with an average port isolation superior to 54 dB (minimum 46 dB) and excellent cross-polarization discrimination. This compact design offers a robust solution for balancing high isolation with stable radiation characteristics.