Millimeter-Wave Radar for Non-Contact Detection of Respiratory and Cardiac Signals: A Comparative Study of Signal Decomposition Algorithms

The advancement of non-contact physiological signal monitoring technology is becoming increasingly important. This study combines millimeter-wave radar and advanced signal processing methods to accurately detect heart and respiratory signals. Variational Mode Decomposition (VMD), Dynamic Bandwidth Variational Mode Decomposition (DB-VMD), Fast Ensemble Empirical Mode Decomposition (fEEMD), and band-pass filters were employed to decompose radar signals into respiratory and cardiac components. The findings demonstrate that VMD and its variants outperform other methods, maintaining high accuracy across different distances and monitoring durations. Experimental results show that DB-VMD can effectively isolate vital signals even in noisy environments, making it well-suited for non-contact health monitoring applications. This study contributes to the development of reliable and user-friendly monitoring systems, enhancing patient comfort.

I. Introduction

Non-contact monitoring of physiological signals, particularly respiratory and cardiac signals, has gained significant attention in recent years due to its potential applications in healthcare and wellness. Conventional contact-based methods, such as electrocardiography (ECG) [1] and thoracoabdominal bands, though precise, may cause discomfort and be restricted for continuous, long-term monitoring. Millimeter-wave radar technology offers a promising alternative, facilitating the non-invasive and contactless detection of physiological signals.