A Dual-Polarized Stacked Dielectric Resonator Antenna Array With Extremely Low Mutual Coupling for 6G Base Stations

This article introduces a stacked dielectric resonator antenna (sDRA) array with dual-polarization for the “golden band of 6G” (7.125–8.4 GHz) applications. The sDRA element consists of three dielectric resonators (DRs) stacked in ascending permittivity, generating multiple low-Q modes, and achieving a fractional bandwidth of 62%. Metal posts are integrated into the sDRA element for improving the isolation between two polarizations, and a decoupling and matching network provides broadband decoupling between sDRA elements. A prototype with 2×2 sDRA elements was fabricated and measured. The isolation between any feeding ports is better than 17 dB within the frequency range of 7.1–8.4 GHz, and the envelope correlation coefficient (ECC) is below 0.02. The proposed method can also be combined with other decoupling structures to construct scalable 2×2 subarrays, achieving an extensive scaling of array size. This article demonstrates 4×4 and 8×8 arrays through full-wave simulation. The sDRA array has compact size, high efficiency, and low coupling, which is potentially useful for 6G massive multiple-input–multiple-output (MIMO) base-station applications.