Study and Development of Wearable Textile Antennas with Metamaterials and EBG Structures

Abstract

In recent years, wearable textile antennas have gained significant attention for their seamless integration into clothing, offering considerable benefits for wireless communication, healthcare, and body-area networks. These antennas are designed to be flexible, lightweight, and comfortable while maintaining high radiation efficiency and gain. However, a key challenge is to enhance antenna performance without compromising wearability, especially under mechanical deformations such as bending and stretching. This PhD thesis presents the design, development, and analysis of a novel, compact, tri-band, apple-shaped wearable textile antenna inspired by metamaterials and backed by a novel Uniplanar Compact Electromagnetic Bandgap (UC-EBG) structure. The antenna is fed using a Coplanar Waveguide (CPW) and is designed for Wireless and Medical Body Area Network (WBAN/MBAN) applications. The proposed printed textile antenna operates at three frequency bands: 2.45 GHz for Wireless Local Area Networks (WLAN), 3.5 GHz for 5G New Radio (NR), and 5.8 GHz for Industrial, Scientific, and Medical (ISM) bands. A novel UC-EBG structure is used as a ground plane to minimize the effect of antenna back radiation on the human body while enhancing antenna performance. Furthermore, metamaterial-based triangular complementary split-ring resonators (TCSRRs) are incorporated into both the antenna and UC-EBG structure, resulting in a compact textile antenna with overall dimensions of 0.41λg × 0.41λg × 0.029λg. The use of jeans fabric as the antenna substrate provides an optimal balance of flexibility, durability, elasticity, and deformation resistance, ensuring seamless integration into clothing. The UC-EBG unit cell is analyzed using the reflection phase, suspended line, and dispersion diagram methods. The integration of the UC-EBG structure resulted in a iii99% reduction in Specific Absorption Rate (SAR) values, achieving values below the safety limits established by regulatory standards in America and Canada (1.6 W/kg for 1g of tissue) and in Europe (2 W/kg for 10g of tissue). The proposed antenna exhibits high gain, with values of 6.68, 7.56, and 8.54 dBi at 2.45, 3.5, and 5.8 GHz, respectively. Its compact size, high performance, and significantly lower SAR values make this design an excellent candidate for wearable healthcare, fitness monitoring, and different WBAN/MBAN applications.