24-GHz Single-Channel Continuous Wave Doppler Radar for Recognizing Diverse Breathing Patterns: A Feasibility Study

Clinical monitoring of breathing patterns using non-invasive methods has gained significant attention due to its non-contact and unobtrusive nature. Previous research has explored various radar configurations, including quadrature channel continuous wave (CW) radar, frequency-modulated continuous wave (FMCW) radar, and ultra-wideband (UWB) radar, to extract breathing patterns. However, a single-channel CW radar offers a simpler architecture and demands fewer signal processing chains compared to its quadrature radar counterpart. This paper evaluates the feasibility of using a 24-GHz single-channel CW radar to recognize three distinct human breathing patterns: normal, fast, and slow. Experimental results demonstrated that simpler-architecture single-channel CW radar could track these three different respiratory patterns with an average accuracy of 94.63% when compared to reference ground truth chest belts.