Eight-Element MIMO Antenna with Closely Spaced Loop Resonators for THz and 6G Systems

This study proposes an innovative terahertz (THz) MIMO antenna architecture comprising four pairs of loop elements, strategically positioned at the four corners of a low-profile Rogers 5880 substrate with dimensions of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$155\times 155\ \mu \mathrm{m}^{2}$</tex>. Each corner integrates closely spaced L-ring/loop resonators, designed to ensure minimal mutual coupling and maintain satisfactory isolation between adjacent elements. The antenna is optimized to operate efficiently within the 4.4–5.2 THz frequency range, offering polarization diversity and enhanced radiation coverage, which are critical for achieving seamless and robust connectivity in high-frequency communication systems. Extensive full-wave simulations have been carried out to evaluate key performance metrics such as gain, efficiency, isolation, and radiation patterns. The results demonstrate the antenna's strong potential for integration into future 6G and THz wireless platforms, where compactness, efficiency, and wide coverage are essential requirements.