High‐efficiency scheme and optimisation technique for design of fragment‐type isolation structure between multiple‐input and multiple‐output antennas

Fragment‐type structure has found its application in designing high isolation structure for multiple‐input and multiple‐output (MIMO) system. In this study, a novel design scheme and a high‐efficiency optimisation searching technique for fragment‐type isolation structure are proposed based on multiobjective evolutionary algorithm based on decomposition combined with enhanced genetic operators (MOEA/D‐GO). Both considering non‐uniform fragment cells in design space and combining two‐dimensional median filtering operator in the original MOEA/D‐GO can improve speed of optimisation searching while obtaining higher isolation and better envelope correlation coefficient at expense of capacity loss. With the high‐efficiency optimisation search, more design objectives including the beam direction can be handled as well. The proposed design scheme and high‐efficiency searching technique are demonstrated through design examples with two MIMO planar inverted‐F antennas operating at 2.345–2.36 GHz and having a centre‐to‐centre interval of 15 mm. Comparison results among three designs verify the high effectiveness of the proposed scheme and optimisation searching technique.