Deployment of Modified Serpentine Structure for Mutual Coupling Reduction in MIMO Antennas

This letter deals with the design and implementation of modified serpentine structure (MSS) for isolation enhancement in microstrip antenna arrays. The antenna array is constructed using square patch radiators and is designed to operate at 2.45 GHz (ISM band) specially used for multiple-input-multiple-output (MIMO) communications. The proposed MSS acts like a band-reject filter to reduce the coupling between the radiators in the antenna array. The design and characterization of the modified serpentine structure is done, and its validity in MIMO scenario is verified through simulation and measurements. Experimental results show an isolation improvement of 34 dB for an array with reduced edge-to-edge spacing of 6 mm (λ₀/20). The envelope correlation coefficient (ECC) is within the acceptable limit, making the solution viable for MIMO applications.