Millimeter-Wave Polarization Dynamics for Non-Invasive Vital Signs Monitoring: A Comprehensive Analysis

This study examines the relationship between incident angle and polarization characteristics of millimeter-wave signals interacting with human tissues, with a focus on axial ratio variations. We designed and analyzed a 24 GHz circularly polarized antenna, using simulations to demonstrate the conversion of left-hand circularly polarized waves to righthand polarized waves upon reflection from the body. Our results show a positive correlation between incidence angle and axial ratio variations. These findings have significant implications for vital signs monitoring, as precise polarization control can enhance signal reception and accuracy, ultimately improving overall system performance. The research contributes to the development of more sensitive and reliable non-invasive monitoring techniques in healthcare applications.