This paper presents designs of novel E-plane spiro meander line uniplanar compact electromagnetic bandgap (E-SMLUC-EBG) and H-plane spiro meander line uniplanar compact electromagnetic bandgap (H-SMLUC-EBG) structures. The proposed EBG has been applied in mutual coupling reduction of a dual-element multiple input multiple output (MIMO) antenna system for WLAN by placing an EBG structure between the radiating antennas. Compact size of EBG helps in reducing the edge to edge distance between antennas which is 0.14λ0 in this case, and it increases the compactness of integrated circuit. It gives 19 dB and 11 dB simulated mutual coupling reduction in E-plane and H-plane respectively at 5.8 GHz. Measured isolation improvement of 20.3 dB for E-plane and 14.7 dB for H-plane has been achieved. This coupling reduction is also confirmed by surface current and correlation coefficient plots. The four-element (2 × 2) MIMO antenna system with proposed EBG is also simulated. © 2018, Electromagnetics Academy. All rights reserved.