Design and Performance Evaluation of a 2×2 Circular Microstrip Patch MIMO Antenna Array for Sub-6 GHz 5G Applications

Electronics and Communication Engineering

This study introduces a compact four-element Multiple-Input Multiple-Output (MIMO) array engineered for the sub-6 GHz 5G n78 frequency band (3.3–4.2 GHz). The proposed structure employs circular microstrip patch radiators arranged symmetrically on a Rogers RO4350B substrate, chosen for its favorable loss characteristics. By leveraging an inset microstrip feed mechanism, the design achieves optimal impedance matching without necessitating complex external circuitry. Full-wave electromagnetic simulations, executed within Ansys HFSS, validate the array’s resonance at 4.02 GHz, achieving a fractional bandwidth of approximately 17% (3.6–4.3 GHz) and a peak realized gain of 5.36 dBi. Critical MIMO metrics, specifically the Envelope Correlation Coefficient (ECC) and Diversity Gain (DG), are calculated to assess system viability. Results indicate an ECC below 0.01 and a DG approaching 10 dB, confirming robust channel isolation. This work demonstrates that geometric symmetry and careful spacing can effectively replace complex decoupling structures, offering a streamlined solution for 5G gateway hardware.

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