Textile-based high-gain bow-tie antenna using metamaterials for medical applications

Abstract

This paper presents a high-gain wearable circularly polarized bow-tie antenna (WCPBTA) with metamaterial unit-cells and 5 pins (5Ps) technique for telemedicine applications such as telemonitoring the elderly or the patients especially for emergency conditions of contagious diseases. The frequency range of the proposed antenna is 5.725–5.850 GHz, which belongs to the unlicensed-national information infrastructure (U-NII-3) for the industrial, scientific, and medical (ISM) sub-channels. A light-weight and flexible felt with dielectric constant ε_r = 3, thickness 1.27 mm, and tan (δ) = 0.0095 is used as the substrate for patient comfort and wearability. The overall dimensions of the proposed antenna are 64 × 62 × 1.27 mm³ or 0.102 λ_g³ at 5.8 GHz. The maximum simulated gain at 5.8 GHz is 8.25 dB, which is more than 4 dB compared to that of the original bow-tie antenna. Besides, the axial ratio (AR) and the specific absorption rate (SAR) are also analyzed, which meet the perfect requirement for medical applications. The fabricated prototype of the antenna shows good compatibility between simulation and measurement results. These characteristics make the proposed WCPBTA a good choice for wireless body area networks (WBANs) in telemonitoring applications especially with the aim of preventing the spread of contagious diseases.