16-Port non-planar mimo antenna system with near-zero-index (nzi) metamaterial decoupling structure for 5g applications

Abstract

In this article, a low-cost 16-port non-planar Multiple-Input-Multiple Output (MIMO) antenna system is proposed for future 5G applications. The non-planar MIMO antenna system is established around a 3D-octagonal-shape polystyrene block. The MIMO elements are arranged on the eight-sides of octagonal-shape block, whereas bottom and top faces of polystyrene block are left void. The single antenna element comprises of slotted microstrip patch with a stepped chamfered feed line and defected ground plane. Each MIMO element is designed on FR-4 substrate with a size of 22 mm 20 mm, to cover the frequency band of 3.35 GHz to 3.65 GHz for the fifth-generation (5G) applications. The isolation between array elements is improved by using a meander-lines based near-zero-index epsilon-negative (NZI-ENG) metamaterial decoupling structure. The array elements are placed on the top-layer, whereas common connected ground plane and decoupling structure is placed on the bottom-layer. The metamaterial-based decoupling structure offers an isolation of more than 28 dB for antenna elements arranged in across and side-by-side configuration. Moreover, simulated and measured MIMO performance parameters i.e. Total Active Refiection Coefficient (TARC) 18 dB, Envelop correlation coefficient (ECC) 0.1 and Channel capacity loss (CCL) 0.3 are in acceptable limits. The proposed non-planar 3D-MIMO antenna system can be employed for indoor localization systems and wireless personal area network applications, where different 5G devices are wirelessly linked to a centralized server. Moreover, a good agreement between simulated and measured results is achieved for the non-planar MIMO antenna system.