A Novel FMCW Radar Scheme with Millimeter Motion Detection Capabilities Suitable for Cardio-Respiratory Monitoring

Area of Science:

• Electrical Engineering
• Biomedical Engineering
• Signal Processing

Background:

• Frequency-modulated continuous-wave (FMCW) radars are widely used for target detection.
• Traditional FMCW radars often require complex synchronization and are sensitive to parasitic coupling, limiting their design and application.
• Accurate detection of micro-movements, such as those from human vital signs, presents a significant challenge for conventional radar systems.

Purpose of the Study:

• To introduce a new modulation scheme for FMCW radars capable of millimeter-level target motion detection.
• To develop a radar system that simplifies design by eliminating synchronization constraints and reducing sensitivity to internal parasitic mutual coupling.
• To enable contactless monitoring of vital signs through the detection of subtle physiological movements.

Main Methods:

• A novel sinusoidal frequency modulation scheme was developed as an alternative to traditional triangular or sawtooth chirps.
• The proposed radar system was designed to be free from synchronization constraints and exhibit low sensitivity to parasitic mutual coupling.
• Numerical simulations and experimental validation were conducted using a 24 GHz radar system.

Main Results:

• The proposed sinusoidal modulation scheme achieved millimeter-level target motion detection capability.
• The radar system demonstrated accurate motion detection even at short distances without specific synchronization procedures.
• Experimental results confirmed the suitability of the modulation scheme for monitoring micro-movements, comparable to human thorax movements during vital activities.

Conclusions:

• The developed sinusoidal frequency modulation scheme offers a simplified yet effective approach for FMCW radar design.
• The radar system is highly suitable for contactless vital sign monitoring, including heart and breath rate.
• This technology presents a promising solution for non-invasive physiological monitoring applications.