Self-Decoupled Dual-Band Dual-Polarized Shared-Aperture Base Station Antenna Array

A self-decoupled, dual-band, dual-polarized, shared aperture antenna array is proposed for base station applications. The slotted patch structure and folded stub loading on the 1.69 2.2 GHz low-band (LB) antenna effectively suppress LB scattering effects while simultaneously generating a partially reflected wave for the 3.3–3.8 GHz high-band (HB) antenna to mitigate coupling between HB elements. Additionally, four circular parasitic elements are arranged around the LB antenna to further reduce coupling among the HB antennas and broaden the LB bandwidth, without requiring additional decoupling layers. A detailed analysis of the decoupling mechanism provided by the slotted patches and folded stubs is conducted. Measurement results confirm that the proposed design achieves excellent decoupling performance, restores the radiation patterns of the HB antennas, achieves an isolation level better than 25 dB, and delivers outstanding performance in both LB and HB frequency bands.