Novel triangular-diamond fractal MIMO antenna with super-wideband capability for portable 5 G/IoT-driven wireless devices

Abstract This research introduces the modeling, simulation, and performance testing of a dual-element, fractal-inspired super-wideband multiple-input multiple-output (MIMO) antenna tailored for applicability in emerging fifth-generation (5 G)/Internet of Things (IoT) networks. The array utilizes a 1.57 mm flame retardant (FR)-4 substrate sheet, covering a 28 × 35.6mm 2 footprint. The array design incorporates two microstrip-fed hexagonal radiators, each embedded with a novel triangular-diamond fractal (2nd iterative) shape on its upper face, yielding an efficient impedance matching across a broad operating spectrum of 2.4–18 GHz with 152.94% fractional bandwidth. Adopting this novel fractal pattern contributes to a 48.25% area reduction relative to the standard hexagonal patch configuration. The partial ground structure, assembled on the rear FR-4 surface, integrates defected ground structure (DGS) and funnel-type decoupling strategies to effectively limit inter-element coupling and signal mismatches. Several diversity performance indicators are assessed and observed to adhere to their prescribed thresholds, confirming the consistency between the simulation and practical measurements. The proposed array is engineered to meet the escalating need for space-efficient, well-isolated antennas in portable electronics, facilitating real-time communication in dynamic 5 G/IoT environments.