Design of a Six-Port Compact UWB MIMO Antenna With a Distinctive DGS for Improved Isolation

Abstract

A low-profile printed six-port ultrawideband (UWB) antenna with a novel decoupling structure for enhancing port-to-port isolation is analyzed in this paper. Six symmetrical pyramidal form UWB antennas with defective ground structures interspersed with parasitic components served as a unique decoupling structure in the proposed design. The grounded branches and modified rectangular stubs on the ground plane generate closed and open current distribution channels, causing the uniform current flow to be disrupted and the coupling effect to be neutralized. The projected six-port antenna has an electrical dimension of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.68\times 0.89 \times 0.01\,\,\lambda ^{3}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> is computed using a lower frequency of 2.9 GHz), having a below -10 dB impedance bandwidth of 116% from 2.9 to 11 GHz. Across the impedance bandwidth, the average port-to-port isolation is better than 20 dB. The antenna design has acceptable radiation properties with a peak gain of 8.3 dBi at a frequency of 7.5 GHz. Further, the projected design is also exposed to the time domain characteristics and diversity metrics. Among the different ports, the values of the group delay and fidelity factors are less than 1.5 ns and more than 0.92, correspondingly. The values of the diversity parameters such as ECC < 0.075, DG approximately 10 dB, MEG <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ &lt; -3$ </tex-math></inline-formula> dB, TARC <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ &lt; -10$ </tex-math></inline-formula> dB, CCL < 0.3 bps/Hz, and ME <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ &lt; -2$ </tex-math></inline-formula> dB ensure that the projected design is appropriate for the MIMO applications. The designed antenna is fabricated and measured, and the results are in line with the simulation.