Compact ACS-Fed IDC-Loaded ELC Metamaterial Inspired Quad-Port MIMO Antenna for Sub-6GHz 5G Applications

Abstract

A novel compact quad-port asymmetric coplanar strip (ACS) fed interdigital capacitor (IDC) loaded electric-inductive capacitor (ELC) metamaterial multiple-input–multiple-output (MIMO) is designed. The electrically small IDC loaded ELC metamaterial inspired quad band single antenna (0.16 λ₀ × 0.1 λ₀) is explored to implement the compact MIMO configuration. The proposed MIMO antenna comprises of four port ACS-fed IDC loaded ELC metamaterial placed orthogonal to each other with footprint of (0.29 λ₀ × 0.29 λ₀). A defected ground structure (DGS) enhanced the decoupling between multiple antennas, providing greater than 30 dB isolation across the operating bands with a spacing of 0.03 λ₀ between antennas. The equivalent circuit for the proposed MIMO antenna is developed to validate the simulated results. The good agreement between the simulated results using ANSYS Electronics simulation and the measured results on the fabricated prototype is validated. The proposed MIMO antenna operates for quad band frequencies 1.2–1.8, 2.1–2.8, 3.2–3.8, and 5.1–5.9 GHz for the application of sub-6GHz 5G New Radio (NG) n51/n53/n78/n46 bands. The computed diversity metrics, such as the envelope correlation coefficient (ECC) < 0.01, diversity gain (DG) > 9.99 dB, total active reflection coefficient (TARC) < −10 dB, channel capacity loss (CCL) < 0.40 b/s/Hz, and the mean effective gain (MEG) < −3 dB, ensure good diversity performance.