Performance Analysis of Patch Antenna Sensors for Non-Invasive Body Electrolyte Monitoring

Abstract

Non-invasive monitoring of electrolyte levels offers significant advantages over traditional blood-based tests, providing less discomfort and enabling continuous monitoring outside clinical settings.This thesis explores the use of microstrip patch antennas (MPAs) for non-invasive electrolyte sensing. It examines three MPA designs: a simple microstrip patch, a spiral engraved sensor patch, and a patch antenna with T-shaped slots. These designs were modeled and analyzed using COMSOL Multiphysics simulations to assess their performance in detecting varying concentrations of sodium chloride (NaCl) in sweat. Key performance metrics such as sensitivity, accuracy, and precision were evaluated based on the reflection coefficient (S11 parameter). The results show that each antenna design has unique advantages and limitations regarding sensitivity to electrolyte changes and practical integration into wearable devices. Innovations in antenna design, such as the RFID-inspired spiral engraved patch and T-slotted patch antennas, show promise in enhancing sensitivity and user comfort for continuous health monitoring. Despite advancements, challenges like environmental interference and the need for greater sensitivity to small biological changes remain. The study shows that the T-slotted patch antenna with a barium titanate slab achieved top sensitivity, precision, and accuracy for detecting NaCl levels in sweat, despite cost and safety concerns. It had the highest accuracy (95.62%), while the spiral engraved sensor patch model excelled in precision with a 0.0026 standard deviation and 7. 00 × 10 variance. The simple −6 microstrip patch antenna offers a cost-effective alternative with 95.51% accuracy. The study highlights the ongoing need for innovative antenna designs to overcome these challenges, ensuring that non-invasive electrolyte sensors can be effectively utilized in healthcare monitoring. This research identifies optimal design parameters for MPAs to enhance non-invasive electrolyte sensing, aiming to advance technology and improve integration into next-generation medical devices.