Wideband coupling suppression with neutralization-line-incorporated decoupling network in MIMO arrays

Abstract

In this paper, a novel neutralization-line-incorporated decoupling network (NLDN) is proposed for wideband multielement antenna arrays. Through introducing additional current path supplied by neutralization line (NL) between antenna elements and decoupling network (DN) between feeding lines but without extra matching network to counteract with the original path, the wideband antenna arrays are well matched and isolated based on network model derivation and node analysis. Four pairs of prototypes are designed to verify the decoupling effectiveness, including two-element symmetric H-plane and asymmetric E-plane coupled antenna arrays, one-dimensional linear and two-dimensional planar ones. Accordant simulated and measured results reveal that the proposed NLDNs for four examples can suppress mutual coupling to below −20 dB in over 20.6% bandwidths, with broadside gains increased, radiation patterns improved, envelope correlation coefficients decreased and total efficiencies enhanced. On account of its followable design process, implementable configuration and wideband decoupling capability, the approach has the potential to be employed in large-scale wideband MIMO antenna arrays.