Design and Performance Analysis of a Metamaterial‐Based Compact High Isolation UWB–MIMO Antenna

ABSTRACT

The ultra‐wideband (UWB) multiple‐input multiple‐output (MIMO) antennas are essential for high‐data‐rate and interference resilient wireless communication systems; however, these antennas face several challenges such as strong mutual coupling caused by the close spacing of radiating elements, degradation of isolation and envelope correlation coefficient (ECC) across the broad UWB spectrum, the difficulty of maintaining wide impedance bandwidth and high radiation efficiency in miniaturized geometries. This paper presents a compact UWB two‐port MIMO antenna integrated with the triple‐T‐shaped double‐negative (DNG) metamaterial (MTM). The triple‐T‐shaped DNG MTM wall significantly improves the port isolation and radiation performance. The MTM based decoupling structure is introduced between the antenna elements to suppress surface‐wave propagation and mitigate near‐field interactions. The antenna, fabricated on an FR‐4 substrate with the dimensions of , achieves a measured impedance bandwidth of 109.97% spanning , covering most of the UWB frequency range and extending beyond it. To suppress mutual coupling between the closely spaced elements, a MTM array, acting as an isolation wall, is introduced between the antenna elements. The proposed design achieves A measured mutual coupling less than dB over the operating range of , with a minimum mutual coupling of dB at 4.21 GHz. The minimum value of the reflection coefficient is at 5.95 GHz, which indicates excellent impedance matching. The antenna attains a maximum gain of 5.65 dB and a radiation efficiency of up to 90%. The MIMO performance metrics confirm the robust diversity characteristics, with the measured ECC consistently below 0.023, diversity gain (DG) approaching 9.95 dB and channel capacity loss (CCL) remaining under 0.5 bits/s/Hz. Surface current analysis further confirms the MTMs effectiveness in suppressing surface wave propagation and improving the isolation. These results demonstrate that the proposed MTM‐integrated UWB MIMO antenna offers an effective, compact and high performance solution for next generation wireless applications, including 5G, IoT, and portable UWB‐enabled systems.