Insights of quad port MIMO antenna for 5G NR n77/n79 to X-bands with reconfigurable grounds using PIN diodes

This manuscript explores the development of a quad-port Multiple-Input-Multiple-Output (MIMO) antenna featuring reconfigurable grounds tailored for 5G NR n77/n79 and X-band applications, utilizing PIN diodes. The research begins with the evolution of a single unit Ultra Wideband antenna, which is subsequently expanded to a reconfigurable grounds 2 × 2 MIMO antenna controlled by a single PIN diode. Further to a reconfigurable grounds 4 × 4 MIMO antenna managed by four PIN diodes. This work is innovative in its approach, as it examines and designs MIMO antennas that can switch between unconnected and connected ground states through reconfiguration techniques. This MIMO antenna is printed on a FR4 substrate, with dimensions of 0.597λ₀ × 0.448λ₀ × 0.0171λ₀ mm³, where λ₀ is determined based on the lowest resonating frequency. It operates across a frequency range of 3.2–12 GHz with connected grounds. In the majority of the band the designs show mutual coupling  ≤  − 15 dB. The performance is assessed at every stage and graphs are compared for both unconnected and connected grounds. The inferences are included on all the metrics like gain, isolation, efficiency, radiation patterns, S-parameters, Mean Effective Gain, Channel Capacity Loss, Diversity Gain, Envelope Correlation Coefficient, and Total Active Reflection Coefficient. The stub introduced to connect the grounds itself act as an efficient decoupling network. The printed MIMO performance results are matches with simulated results. This work has 5G wireless applications including RF energy harvesting and cognitive radio.