Flexible leather substrate dual-band wearable antenna with impact analysis on testing under wet condition for human rescue system

Wearable flexible antennas have yielded much attention in recent years because of their interesting features and capabilities for enabling flexible, lightweight, portable and low cost wireless communication. The proposed research work offers the design of the flexible wearable patch antenna with four single Split Ring Resonators (SRRs) using a leather substrate for better performance. The proposed antenna is designed and simulated with leather substrate at the operating frequencies of 0.99 GHz and 3.5 GHz. The antenna is fabricated and validated under free space (normal condition), partially wet, fully wet and dried after wet conditions using Vector Network Analyzer (VNA). Different parameters such as reflection coefficient, Voltage Standing Wave Ratio (VSWR) and gain of the fabricated antenna are measured, and they are compared with the simulation results. The validated results show that the performance of the proposed antenna under free space, partially wet, fully wet and dried after wet conditions is virtually equal. The Specific Absorption Rate (SAR) of this proposed antenna is also investigated for 10g tissues and the SARs are 0.0168763 W/kg and 0.69567 W/kg at the operating frequencies of 0.99 GHz and 3.5 GHz, respectively. As a result, its good performance in wet conditions along with low cost and ready availability of leather material means the proposed antenna can be used for human safety environments, especially in military applications, etc.