Publication

Abstract : This paper presents the design of a conformal microwave sensor (CMWS) operating at the 1.75 GHz band, developed to analyze electrolyte components in sweat solutions to predict multiple health conditions. The sensor detects concentrations of key sweat components such as KCl, NaCl, lactic acid, and urea by analyzing shifts in resonant frequency corresponding to variations in the dielectric properties of sweat. The proposed CMWS design incorporates two symmetrically arranged, directly coupled geometrically modified split-square resonators, interconnected, and centered around a square-shaped detection region. A small amount of artificial sweat with varying dielectric constants is introduced onto this CMWS, allowing for differentiation between electrolyte concentrations through analysis of resonant frequency shifts. An ESP32 microcontroller is integrated to facilitate real-time monitoring and wireless transmission of sweat analysis data, enabling immediate health alerts. The fabricated prototype, measuring 0.3λo × 0.63λo, is constructed on a 0.1-mm-thick polyimide substrate and validated through real-time measurements, demonstrating its capability for precise and noninvasive sweat analysis.