Measurement analysis of eight-port ultra compact MIMO antenna with eye-slot and defected ground (ES-DGS) structure including parasitic patch with dual-band millimeter wave characteristics

Abstract This paper reports an ultra-compact Eight-port MIMO ES-DGS antenna with an overall dimension of 32 × 32 × 0.254 mm 3 printed on an ultra-thin Rogers Duroid substrate with conformal characteristics. The radiating patch consists of a circular patch with an Eye-shaped pattern on the top surface and a defected ground structure (DGS ES-DGS ) with a parasitic circular patch on the opposite surface. The pair of slots on either side of beneath the feedline bifurcates the Band1 and Band2 and is used as a filter. The single-port version offers good time-response with faithful reception of the transmitted in face-to-face and side-to-side orientations with stable minimal variation group delay. The MIMO ES-DGS antenna offers measured −10.0 dB bandwidth of 12.38 GHz–19.94 GHz (Band1) and 22.60 GHz–53.53 GHz (Band2) with measured isolation of more than 15.0 dB. The proof of reduced mutual coupling between the inter-spaced is also validated by surface-current-density distribution corresponding to frequencies of 15.0 GHz, 28.0 GHz, 38.0 GHz, and 47.0 GHz. The diversity parameters are within the standard acceptable range of ECC ES-DGS &lt; 0.50, DG ES-DGS <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≅</mml:mo> </mml:math> 10.0 dB, TARC ES-DGS &lt; 0.0 dB, CCL ES-DGS &lt; 0.40b/s/Hz and MEG ES-DGS <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≅</mml:mo> </mml:math> −3.0 dB. The MIMO ES-DGS antenna is also studied by bending the Eight-port prototype at different angles with the phantom head used in SAR analysis. The MIMO ES-DGS antenna offers a maximum peak-realized-gain of 5.97 dBi with an efficiency of more than 94% and acceptable 2D-radiation patterns.