A Compact Two-Port Semi-flexible Dual-Band Circularly Polarized MIMO Antenna Structure for Millimeter-Wave 26/31 GHz 5G Applications

This article introduces a novel semi-flexible dual-band-printed MIMO antenna designed for 5G communication systems at 26 and 31 GHz in the mm-wave spectrum. The antenna, featuring a radiating decagonal patch with integrated multiple slots, achieves dual-band impedance bandwidth and circular polarization. With notable gains of approximately 8.74 dBi and 6.62 dBi at 26 GHz and 31 GHz, respectively, and an axial ratio below 3 dB at 26.4 GHz, the antenna demonstrates commendable circular polarization performance. The study addresses mutual coupling, optimizing interference effects to achieve substantial isolation levels exceeding 20 and 30 dB, with an ECC below 0.0001. A diversity gain exceeding 10 is documented for the 26 and 31 GHz bands. This MIMO antenna holds a promise as an efficient millimeter-wave radiator solution for advanced 26/31 GHz 5G applications.