Hybrid Decoupling Structure Based on Neutralization and Partition Schemes for Compact Large-Scale Base Station Arrays

This letter proposes a hybrid decoupling structure consisting of a neutralization dielectric board, metal baffle, and feeding network to enhance the isolation in a compact large-scale base station array. Both the neutralization- and partition-based schemes are utilized to reduce the mutual coupling between antennas. The neutralization dielectric board provides a new signal path to cancel the original mutual coupling, and the metal baffle is employed to suppress the propagation of the space electromagnetic wave. The antenna elements in the vertical direction are excited by a feeding network. A 4×4 dual-polarized antenna array with a horizontal edge-to-edge distance of 0.38 free-space wavelength is designed and fabricated to demonstrate the effectiveness of the proposed structure for large-scale arrays for base station application. Simulated and measured results show that the voltage standing wave ratio is less than 1.7, and the isolation between any two ports in the array is better than 20 dB within the entire operating frequency band. Stable radiation patterns with a good front-to-back ratio and cross-polarization ratio are achieved.