DefinePK

Abstract

This paper presents the design, optimization, and performance analysis of a compact four-port ultra-wideband (UWB) MIMO antenna for next-generation high-frequency communication systems. The antenna is built on a Rogers RT Duroid 5880 substrate and operates effectively in the 12.5–55 GHz, range making it suitable for millimeter-wave 5G applications. A four-step design process is used to develop a single antenna element optimized for wide bandwidth and good impedance matching. Parametric studies on feedline length, inset depth, and ground structure help improve bandwidth and ensure strong radiation patterns. In the MIMO setup, four radiating elements are placed at right angles to each other to reduce mutual coupling. Additionally, a centrally located plus- shaped decoupling resonator is added to further improve isolation, especially at lower frequencies, enhancing overall antenna performance. Simulation results show excellent impedance matching, a very low envelope correlation coefficient (ECC < 0.004), and a high diversity gain (dB). The antenna also delivers stable radiation patterns and high efficiency (>85 %) across the operating range. These findings confirm that the proposed MIMO antenna offers strong isolation (<-20dB), compact size (20x20 mm2), and wide bandwidth (40GHz) making it a suitable choice for future UWB and millimeter-wave MIMO systems.