Opportunistic control of fractal‐based MIMO antenna for sub‐6‐GHz 5G applications

Summary The proposed research work is on fractal MIMO antenna with microstrip feeding for lower sub‐6 GHz. The design construct's goal is to improve the isolation among the patches and is constructed with a combination of circular strip and rectangular strip slots, and rectangular slots are introduced on the ground plane. The fractal‐shaped MIMO structure composes of FR‐4 material and compact size of 25 × 35 mm2. The current 2 × 1 fractal MIMO radiator resonates at a frequency 3.5 GHz for lower sub‐6‐GHz applications with directional radiation patterns. In this structure, the performance characteristics of design antenna parameters like S‐parameters, surface current distributions, and radiation pattern of the fractal MIMO radiator are investigated. In addition to antenna parameters, MIMO parameters like diversity gain (DG), mean effective gain (MEG), channel capacity loss (CCL), total active reflection coefficient (TARC), and time‐domain analysis parameters are also evaluated. It has been observed that the MIMO parameters of the antenna are in the acceptable range. Fractal‐based prototype MIMO structures are fabricated as well as tested for effective radiation and impedance. The improvised MIMO design that's been installed on a printed circuit board with connector, device housing, compact size, and various types of housing shows better performance compared to the conventionally designed antennas. This research article presents fractal MIMO structure with compact size (25 × 35 mm) and high isolation that is designed for lower sub‐6‐GHz 5G applications. It consists of rectangular strips, circular strips, and introduced fractal circular slots and rectangular slots on the ground plane. Furthermore, the performance of diversity MIMO structure in terms of diversity gain (DG), channel capacity loss (CCL), envelope correlation coefficient (ECC), total active reflection coefficient (TARC), and mean effective gain is also evaluated.