Compact Wideband MIMO Antenna Design with Enhanced Isolation for IoT and Wearable Wireless Applications

Abstract

There is a growing use of Internet of Things (IoT) devices and wearable wireless
devices, which has accelerated the need to develop small and low-profile antenna
designs that can be used to achieve reliable high-data-rate communication in highly
space-constrained systems. Spectral efficiency and the link robustness are commonly
improved using multiple-input multiple-output (MIMO) technology, although the high
mutual coupling among tightly spaced antenna elements is still a major problem in
compact and body-centric devices and causes poor impedance matching, radiation
efficiency, and diversity performance. This paper describes a small wideband two
elements MIMO antenna with improved isolation in the IoT and wearable wireless
customization. The antenna is done by a planar format and integrates a basic, fabrication
friendly, isolation architecture into the ground plane to stop the interaction of surface
current between antenna elements. The simulations are the full-wave electromagnetic
simulations to optimise the antenna geometry and isolation structure in the broadband
operation and high inter-element isolation. The optimized design has a wide scope of
operation, operating in 2.3-6.0 GHz with over 20 dB of inter-element isolation over the
operating band, and its wide bandwidth. A detailed analysis of the MIMO performance
shows the existence of excellent diversity properties where the envelope correlation
coefficient is at 0.01 (or less) capability of critical diversity, low channel capacity loss,
and balanced effective mean gain. In addition, the antenna functionality is also studied
in the wearable conditions of operation using a human body phantom, and the specific
absorption rate analysis is used to verify an adherence to international safety standards.
The result of the simulation is verified with the help of the experimental measurements
of a constructed prototype. The presented antenna is a compact, cost-effective, and
strong device that should be included in the next-generation wearable and IoT wireless
infrastructure, thus the proposed antenna is highly applicable to the interactions with
the body