Conjoint Coupling Lessening in Multiband MIMO Antenna Using Cross-Slot Fractal Multiband EBG in the E-Plane

Abstract

This paper presents the design and implementation of a multiband Electromagnetic Band Gap (EBG) structure integrated with a multiband Multiple-Input Multiple-Output (MIMO) antenna system for reducing mutual coupling between antenna elements. An EBG structure is a periodic arrangement of dielectric or metallic materials that acts as a filter for electromagnetic waves by suppressing the propagation of specific frequency bands while allowing others to pass. The proposed multiband EBG structure is designed to operate at 5.7 GHz, 7.5 GHz, and 10 GHz, enabling simultaneous suppression of unwanted electromagnetic interactions at multiple frequencies. The proposed MIMO antenna system employs multiple antenna elements at both the transmitter and receiver to enhance communication performance in terms of data rate, reliability, and spectral efficiency. However, close placement of antenna elements often leads to mutual coupling, where electromagnetic fields from adjacent antennas interfere with each other, degrading overall system performance. To address this issue, the proposed multiband EBG structure is incorporated between antenna elements to significantly reduce coupling effects. The performance of the proposed design is evaluated using important MIMO parameters such as Envelope Correlation Coefficient (ECC) and Channel Capacity Loss (CCL). A low ECC value indicates high signal independence between antenna elements, while reduced CCL demonstrates improved communication efficiency. Simulation and experimental results confirm that the proposed multiband EBG-based MIMO antenna achieves effective mutual coupling reduction and enhanced overall system performance across the targeted frequency bands.