Integrated Microstrip Patch Antenna with a Frequency-Selective Surface Utilizing Hospital Textile Materials for Reduced Specific Absorption Rate in Wearable Wireless Communication Systems

This work proposes an antenna integrated with a frequency-selective surface (FSS) for applications in medical continuous monitoring systems with a reduced specific absorption rate (SAR). The antenna and FSS were fabricated on textile substrates made of cotton and polyester, which are used in textile products for health. The array operates at a frequency of 2.4 GHz. We selected three textile materials, each with varying proportions of cotton and polyester, for designing the antennas and FSS. Electrical characterization of the materials was conducted. The antenna was designed for a filled ground plane and rectangular patch fed by a microstrip line. The FSS was designed using square loops. The experimental operation of the FSS within the range of interest was observed through the transmission coefficient as a function of frequency. Phantoms were fabricated to simulate human tissues. We conducted a thermal analysis to assess the impact of continuous exposure to signal transmission from the integrated antenna. Results demonstrated a reduction in SAR of 77.78% relative to the antenna without the FSS, due to the effective rejection of the ISM (industrial, scientific, and medical) band signal by the FSS.