FSS-Based Spatially Decoupled Back-to-Back Four-Port MIMO DRA With Multidirectional Pattern Diversity

Abstract

This letter presents a frequency selective surface (FSS)-based four-port multiple-input-multiple-output cylindrical dielectric resonator antenna (cDRA) system that supports multidirectional pattern diversity characteristics. The back-to-back arrangements of the cDRA as well as the use of an FSS are some of the features of the proposed antenna design. The cDRAs are positioned over a substrate through a common ground plane. The top side has two oppositely faced cDRAs that are excited with the help of ports-1 and 2, via coplanar waveguide-fed conformal striplines. Similar cDRA orientations also exist at the bottom side and are excited by microstrip-line-fed conformal striplines through ports-3 and 4, respectively. To improve isolation and correlation, similar phase-gradient FSSs are placed at the two sides of the substrate. As a result, four diverse radiation patterns are obtained from four ports, which ensure multidirectional pattern diversity characteristics of the proposed antenna. The proposed technique offers more than 10 dB and 75% improvement in isolation and correlation values, respectively. By observing the measured results, it is confirmed that the proposed structure is useful for WLAN access point (5.15-5.35 GHz) applications.