Wideband 20-Elements 3D-MIMO Antenna for Localization System

In this brief, a low-profile wideband quad-element MIMO antenna with high isolation is designed, which is utilized to propose a 20-elements MIMO system. Each element of the MIMO antenna covers a wideband occupying a small area of
$15\times 15$
mm
²
. The orthogonal symmetric arrangement of a single antenna forms an extremely compact quad-element MIMO antenna having shared ground, and its occupied volume is
$0.84\lambda _{\mathrm{ g}} \times 0.84\lambda _{\mathrm{ g}} \times 0.019 \lambda _{\mathrm{ g}}$
(
$\lambda _{\mathrm{ g}}$
at 3.95 GHz) with a minimum (
$0.155 \lambda _{\mathrm{ g}}$
) edge to edge distance between elements. The proposed antenna has a −10 dB (
$S _{ij} \in i=j$
) impedance bandwidth of 77.52% (3.95–8.95 GHz) and a minimum isolation (
$S _{ij} \in i \ne j$
) value of 17 dB. The measured and simulated results are found in good agreement that confirms the proposed antenna is appropriate for extending a higher-order MIMO system. Further, a low-profile quad-element MIMO antennas are arranged orthogonally at the four-corners and a quad-element MIMO antenna at the center of form a 20-elements planar MIMO antenna. It can be utilized as a localization system where different user’s devices are connected to the primary host.