Design and analysis of compact 8-port dual-element MIMO antenna for wireless applications utilizing classical electromagnetic CMA approach

Abstract

A compact 8-port antenna of size 0.64λ0× 0.64λ0× 0.01λ0 (λ0 is lowest operating wavelength at 3.2 GHz) with dual-element MIMO configuration is proposed in this study. The integrated multi-port system has 4 × different antenna configurations, assisting discrete operating modes (Ant-On as odd numbered antennas, Ant-En as even numbered antennas, where n = 1, 2, 3,….., 8) and are investigated through electromagnetic modal analysis using CMA approach. The Ant-On elements has an inverted L-shaped monopole with broadened feed and narrowed at junctions. To improve impedance matching,4-nested CSRR loops are loaded as magnetically coupled induced resonator. The 4 × Ant-On operates from (3.35–4.08) GHz of IBW ≈ 20%. Similarly, the Ant-En elements has an linear monopole element with electrically coupled two L-shaped resonating stubs assisting wideband performance. The 4 × Ant-En operates from (3.2–5.32) GHz of IBW ≈ 40%. There is no decoupling network and the coupling coefficient is > 15 dB, by splitting the grounds of each antenna elements with L-shaped and stepped ground topologies. To invoke pattern diversity, Ant-On and Ant-En elements are placed side-by-side and are sorted orthogonally to mimic radiation diversity. The ECCFar-field(ρ1n)< 0.13 with (4–5.4) dBi as realized gain and radiation efficiency > 60% in the operating spectrum. A prototype antenna was fabricated and measured with good results to be potentially explored in wireless applications.