Design and analysis of a flexible substrate-based low mutual coupling MIMO antenna for On-Body wireless medical telemetry, 5G, and military communication applications

Abstract In this work, a versatile, low mutual coupling, circularly polarized Multiple-Input-Multiple-Output (MIMO) antenna is presented on a flexible polyimide substrate, specifically designed for multiband on-body wireless communication applications. The antenna is implemented on a compact 30 × 50 mm 2 polyimide substrate, making it lightweight, conformal, and highly suitable for wearable and body-centric systems. The patch and ground planes are modified with several structural enhancements to improve the performance and to achieve circular polarization. The ring-shaped patch elements were developed for proper impedance matching, and the T shaped rectangular stub on the ground plane, along with a rectangular slot at the centre, are incorporated for enhanced isolation and mutual coupling suppression. The propounded antenna structure results in an efficient multiband performance at 1.4, 3.1, and 4.7 GHz operating at bands of On-Body Wireless Medical Telemetry, Fifth-Generation (5G), and Military Communication Applications. The presented MIMO has high radiation efficiency, good Total Active Reflection Coefficient (TARC) and very low Envelope Correlation Coefficient (ECC) and a Diversity Gain (DG) near 10 dB, which verifies the excellent MIMO performance. Furthermore, the low Specific Absorption Rate (SAR) of the antenna makes it safe for wearable body-centric applications. The mechanical flexibility of the proposed antenna enables its steady performance even under bending and deforming conditions, which suggests its reliability in practice. With the compact size, multiband, reduced mutual coupling, and reliable operation, the proposed antenna provides an efficient and technologically advanced solution for next-generation 5G systems, Internet of Things (IoT)-based biomedical sensing, military communications, and smart wearable devices.