A Half Hexagonal Fractal L-Band Antenna With SAR Analysis For Wearable Application

This paper presents the design, comprehensive analysis, and experimental validation of a flexible, wearable antenna optimized for operation in the L-band frequency spectrum. The proposed antenna utilizes a coplanar waveguide (CPW) feeding structure and is realized on a polyethylene substrate characterized by a dielectric constant of 2.5 and a thickness of 1.5 mm. With compact dimensions of 90 × 144 × 1.5 𝑚𝑚3, the antenna offers excellent mechanical flexibility, low profile, and high radiation efficiency, making it ideally suited for integration in wireless body area networks (WBANs) and medical telemetry systems. Electromagnetic simulations and prototype measurements confirm broadband impedance matching, consistent radiation patterns, and stable gain performance under various bending radii, ensuring mechanical robustness and electromagnetic reliability in dynamic on-body conditions. To assess user safety and electromagnetic exposure, a specific absorption rate (SAR) analysis is performed using a three-layer human tissue-equivalent phantom for both 1gram and 10-gram tissue masses. Evaluations are conducted across multiple proximity scenarios, including direct skin contact and spatial offsets of 1 mm, 3 mm, and 5 mm from the body surface. The observed SAR values comply with international safety standards, remaining below the regulatory thresholds of 1.6 W/kg (IEEE) and 2.0 W/kg (ICNIRP), thereby confirming the antenna’s viability for safe and reliable use in wearable biomedical applications.