3-D Beam-Steering MIMO Antenna for On-Body IoT Applications

Abstract

In this article, a compact 3D beam-steering MIMO antenna operating at 5.75 GHz is proposed for on-body Internet of Things (IoT) applications. The planar antenna comprises a central patch and two concentric annular rings. The theory of spherical modes is used to discuss the beam-steering concept, where the free space measured beam-scanning covers the entire xy-plane, while a 44° range is realized in xz and yz-planes. The on-body performance is tested using a multi-layer phantom, and the measured peak realized gain is 6.41 dBi. The antenna is characterized by compact size (0.77λ), low profile (0.03λ), specific absorption rate below the established limits, good efficiency and 3D beam-steering characteristics while operating in an on-body setup. Therefore, the proposed solution can enable advanced wireless applications like localization and physical layer security in emerging size-constrained on-body IoT devices.