Highly Penetrative Chest-Worn Metasurface for Multi-Angle RADAR-Based Vital Sign Monitoring.

Area of Science:

• Biomedical Engineering
• Electromagnetics
• Metamaterials

Background:

• Radar-based vital sign monitoring faces challenges with electromagnetic wave penetration through biological tissues.
• Existing solutions often lack practical applicability for continuous, real-world health monitoring.
• Metasurfaces offer potential for improved wave manipulation but require wearable integration.

Purpose of the Study:

• To present a novel chest-worn, highly penetrative reflectionless metasurface for enhanced radar-based vital sign monitoring.
• To address limitations in electromagnetic wave transmission through diverse biological tissues and body orientations.
• To validate the practical applicability of the metasurface in a wearable form factor.

Main Methods:

• Design and implementation of a 60 GHz reflectionless metasurface integrated into a wearable device.
• Validation using realistic human tissue models and multi-angle configurations.
• Performance evaluation of radar system accuracy for heart rate monitoring against electrocardiogram (ECG) benchmarks.

Main Results:

• The metasurface demonstrated excellent electromagnetic wave penetration across various body compositions and orientations.
• The wearable radar system achieved highly accurate heart rate monitoring, with bias < 0.01 Hz compared to ECG.
• Performance was validated even under challenging multi-angle and varied tissue conditions.

Conclusions:

• The developed wearable metasurface significantly enhances radar-based vital sign monitoring.
• This reflectionless metasurface technology bridges the gap between lab designs and real-world applications.
• It offers a robust, non-invasive solution for precise and reliable continuous health monitoring in dynamic scenarios.