Pretty-small four-port dual-wideband 28/38 GHz MIMO antenna with robust isolation and high diversity performance for millimeter-wave 5G wireless systems

Planar MIMO antenna for mmWave applications: Evolution, present status & future scope

“…The equations and the minimum threshold value of these parameters are specified in Refs. [ [55] , [56] , [57] , [58] ].

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“…The MIMO antennas designed in Refs. [ 56 , [78] , [79] , [80] , [81] , [82] , [83] , [84] , [85] , [86] ] don't share the common ground point, which obviously results in better isolation S ij between the ports. And also, these are arranged in 180 0 /orthogonal orientation to reduce mutual coupling and enhance isolation.…”

“…The MIMO design in Refs. [ [80] , [81] , [82] , [83] , [84] , [85] , [86] ], and [ 56 ] are the 4-port element which is orthogonal/180 0 oriented for better isolation with the partial ground plane. In Ref.…”

“…Similar to the earlier design, a modified line resonator of a fan-shaped decoupling structure is etched on the top and bottom of the Rogers 5880 substrate [ 56 ]. The single element is an elliptical patch with a 50 Ω feed line, this created resonance at 33 GHz and 43 GHz.…”

“…It has increased the isolation of −30 dB and higher throughout the band. The performance of these MIMO antennas is as follows: bandwidth 27.6–29.7 GHz, 27.6–28.4 GHz/37.9–38.5 GHz, 26–29 GHz, 27–28 GHz/37.2–38.8 GHz, 23.6–31.5 GHz, 26.5–30.8 GHz, 24.2–37.8 GHz, and 27–28.8 GHz/36–38.7 GHz, gain 6.1 dBi, 7.9 dBi, 6.5 dBi, 7.95/8.27 dBi, 5.66 dBi, 8 dBi, 6.4 dBi, 6 dBi/5 dBi, isolation −29 dB, −28 dB, −25 dB, −30/-24 dB, −27.5 dB, −22.5 dB, −27 dB, −30 dB/−32.5 dB and radiation is omnidirectional [ 80 ], broadside with 35 0 in E− and H-plane [ 81 ], omnidirectional [ 82 ], broadside with 60 0 at 28 GHz, 90 0 at 38 GHz in E-plane [ 83 ], omnidirectional [ 84 ], bidirectional with 110 0 in E-plane [ 85 ], bidirectional with 60 0 and 70 0 in E− and H-plane [ 86 ], 75 0 and 90 0 in E− and H-plane at 28 GHz/90 0 in E− and H-plane at 38 GHz [ 56 ]. The performance metrics of DGS non-common ground MIMO antennas are shown in Fig.…”