Design of compact dual-polarized multiband MIMO antenna using near-field for IoT

摘要

This paper presents the integration of the unlicensed ultra-wideband (UWB) with the existing bands like the 1.9 GHz long-term-evolution (LTE) band and 2.4 GHz industrial scientific and medical (ISM) band to cater for the diverse need of the upcoming internet of things (IoT) technology. The designed compact tri-band antenna has a dimension of 33 x 18 mm(2) (i.e. 0.24 x 0.114, where 4 is calculated at 1.89 GHz in the free space). This antenna provides high-quality factor (Q) and narrow-band impedance matching at the 1.9 and 2.4 GHz bands with about 2.9% and 4.7% bandwidth respectively, which is sufficient for those IoT applications, which are supposed to support low data rate communication. Further, the tri-band antenna is found to be effective for IoT as the hosting effect is within the tolerable range. Finally, multiband polarization diversity antenna is designed having a size of only 33 x 57.25 mm 2 (0.24 x 0.364) to combat the depolarization effect of signals in the indoor environment. Near-field simulations are carried out to determine the best position/orientation of MIMO elements in order to improve port-to-port isolation and envelope-correlation-coefficient (ECC). The minimum isolation and maximum ECC are found to be 14.2 dB and 0.0471, respectively across all the operating frequency bands. (C) 2020 Elsevier GmbH. All rights reserved.