Mutual Coupling Reduction With Dielectric Superstrate for Base Station Arrays

This letter proposes a dielectric superstrate to reduce the couplings between copolarized and cross-polarized antenna elements in realistic base station (BS) arrays. The mutual couplings are reduced by adjusting the permittivity and profile of the dielectric superstrate to create "reflected" waves to neutralize the original coupling wave. The dielectric superstrate is a simple structure that is easy to design and manufacture. A large dielectric board and four small dielectric blocks help reduce the couplings between horizontal and vertical antenna elements, whereas a dielectric pillar is added to suppress the coupling between diagonal elements. The superior decoupling performance (>25 dB isolation) is demonstrated for dual-polarized BS arrays over the fifth generation frequency band of 3.3-3.8 GHz, without affecting the matching and radiation performances of the array elements.