Wideband Isolation Enhancement of Dual-Antenna Array Using Hybrid Decoupling Structures

A wideband hybrid decoupling structure for MIMO antennas is presented in this paper. The decoupling structure is composed of a suspended array-antenna decoupling surface, which consists of several reflectors and a defected ground structure with two rectangular slots to reduce the mutual coupling. When utilizing the proposed design in the two extremely-closed patch antennas with an edge-to-edge distance of only 1 mm (0.019 λ
0
at 5.65 GHz), the simulated results demonstrate that the isolation better than 20 dB can be achieved over the frequency range of 5.13-6.27 GHz (20%). Besides, the isolation level reaches more than 30 dB over 5.41-6.25 GHz (14.4%). Meanwhile, the efficiency and gain of the antenna are also improved by considerable amounts.