Dual-circular slotted low-profile ultrawideband textile MIMO antenna with ground slot stub for Sub-6G, ISM, and IoT applications

Abstract

This paper presents a novel, compact, and a dual-port MIMO antenna designed for ultrawideband, Sub-6 GHz, Industrial, Scientific, and Medical (ISM) band, and Internet of Things (IoT) applications. The antenna uses a stretchable jeans textile substrate embedded with elastomeric materials, enhancing its dielectric properties and flexibility. The innovation in this design stems from the introduction of defects (slots) on the stubs connected to a partially etched ground plane, which significantly improves isolation, achieving a port isolation of 47.5 dB which is superior to conventional designs. Operating across a wide frequency range of 2.82–14.23 GHz, it supports critical bands including WLAN, WiMAX, RAS, N79, C-band, and Sub-6 GHz, making it ideal for next-generation wireless systems. The antenna, with its compact footprint of 50 × 35 mm², also covers ISM applications (2.4 GHz/5.8 GHz), making it versatile for medical and industrial communication needs. It delivers excellent performance, including a return loss (S₁₁) below −10 dB, diversity gain above 9.95, and channel capacity loss below 0.25 bits/s/Hz. Additionally, it maintains a mean effective gain below 0.16 dB, an envelope correlation coefficient under 0.054, and a peak gain of 3.97 dB with over 82.45% radiation efficiency. These features make the proposed antenna a significant advancement, suited for future communication systems, wearable devices, and IoT-based Sub-6 GHz and ISM band applications.