Isolation Enhancement of Metamaterial-Inspired Two-Port MIMO Antenna Using Hybrid Techniques

This brief utilizes hybrid isolation enhancement techniques to design a highly isolated two-port multiple-input-multiple-output (MIMO) antenna. Initially, an epsilon-negative transmission line-inspired antenna with circular polarization (CP) radiation is designed. Further, the same antenna is converted into a two-element MIMO configuration. Higher antenna isolation is obtained mainly due to two factors. Initially, multiple defected ground structure-based slots are inserted in the antenna ground plane to improve the antenna isolation by 23.5 dB. Secondly, placing an epsilon-and-mu-near-zero-based metasurface superstrate above the two-port MIMO configuration results in bandwidth ranges from 4.768–4.92 GHz and higher isolation of 51 dB. Finally, for analyzing the antenna performance in an actual environmental condition, the multilayer MIMO antenna is covered with a Teflon cavity and analyzed. Furthermore, the antenna port-1 provides right-handed CP radiation, while port-2 provides left-handed CP radiation, confirming the polarization diversity performance.