Compact Self-Isolated Extremely Low ECC Folded-SIW-Based Slot MIMO Antenna for 5G Application
Amit Kumar Singh, Srikanta Pal
Abstract
This letter proposes a compact, self-isolated extremely low correlated, 1×4 folded-SIW-based slot antenna configuration for a 5G multiple-input–multiple-output (MIMO) communication system operating at 38 GHz band. To minimize the near-field coupling between the feed lines and ensure impedance matching at the microstrip (MS) to T-type folded substrate integrated waveguide feeding (TFSIW) section, the capacitive and longitudinal currents at the input section of the TFSIW are precisely tuned by adjusting the position of lateral walls and optimizing the dimension of the central wall and septum. The compactness of this antenna is attained through the utilization of a TFSIW, which possesses a high compression ratio resulting in a total MIMO size of 9.8 × 38.64 × 0.508 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The self-isolated MIMO antenna offers an impedance bandwidth of 7.17% (36.5–39.28 GHz), a maximum gain of 10 dBi, minimum isolation of 30 dB. The envelope correlation coefficient (ECC) remains below 3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−5</sup> , whereas the diversity gain (DG) exceeds 9.99993 dB. The radiation efficiency remains over 90%, the minimum cross-pol difference (XPD) is 20 dB, maximum side lobe level (SLL) remains around −15 dB in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">XZ</i> -plane. The measured results closely match the simulated one. Furthermore, the proposed design demonstrates enhanced performance and higher compactness when compared to the recent and limited state-of-the-art works.