Small-Size Eight-Element MIMO Metamaterial Antenna with High Isolation Using Modal Significance Method.

Area of Science:

• Electrical Engineering
• Electromagnetics
• Metamaterials

Background:

• Modern wireless communication systems, particularly 5G New Radio (NR), demand antenna arrays with high performance and miniaturization.
• Achieving high electromagnetic isolation in closely spaced antenna elements is a significant challenge in Multiple-Input Multiple-Output (MIMO) systems.

Purpose of the Study:

• To design and validate a symmetrical, reduced-size eight-element MIMO antenna array for n77 and n78 NR bands.
• To enhance electromagnetic isolation between closely packed antenna elements.
• To achieve significant size reduction compared to conventional antenna designs.

Main Methods:

• Utilized an octagonal double-negative metamaterial split-ring resonator (SRR) for radiator size reduction.
• Employed the modal significance (MS) method to analyze electromagnetic coupling.
• Implemented electromagnetic barriers using strip lines to mitigate coupling effects.

Main Results:

• Achieved over 50% size reduction in radiators using SRR metamaterials.
• Attained isolation exceeding 20 dB for adjacent and 40 dB for opposite elements.
• Demonstrated excellent MIMO performance with envelope correlation coefficient (ECC) < 0.0001 and diversity gain (DG) ≈ 20 dB.

Conclusions:

• The proposed symmetrical, reduced-size eight-element MIMO antenna array effectively addresses the need for compact and high-performance antennas in 5G NR.
• The integration of metamaterial SRRs and electromagnetic barriers provides a viable solution for enhancing isolation in dense antenna arrays.
• The array's small footprint (0.32 λ^2 at 3.5 GHz) and superior performance metrics make it suitable for advanced MIMO applications.