Improves the Accuracy of Non-Contact Detection of Vital Signs
This compact 60-GHz microradar system and algorithm offer more effective non-contact vital sign detection despite normal interference from respiratory wall movement. Doppler radar systems are used for non-contact vital sign and mechanical vibration detection because they can be very-low-power, cost-effective, and function at longer distances and through walls. However, respiratory chest-wall movement causes a nonlinear Doppler phase modulation at 60 GHz, making accurate detection much more difficult.
Researchers at the University of Florida have developed a radar system that uses a Doppler radar signal recovery algorithm to detect accurately the heartbeat and respiration rates of a patient with a 60-GHz signal, despite signal interference from respiratory chest wall movement. This design is the first to ensure accurate vital sign detection at 60 GHz.
Microradar system for non-contact vital sign detection that accounts for possible signal interferences
- Accounts for the possible interference of respiratory wall movement, providing accurate detection of respiratory and heart rates
- Detects non-contact vital signs and vibration at 60 GHz, providing high accuracy detection at long distances
- Requires smaller antennas and components, making a more compact system and reducing integration costs
- Can implement radar chip in low-cost complementary-metal-oxide semiconductor (CMOS) process, making it easy to integrate radar system and antennas into smartphones and tablet devices for daily use
Respiratory chest walls move at a 60-GHz frequency, causing a nonlinear Doppler phase modulation in the detection signal, which introduces harmonic and inter-modulation peaks. These frequency interferences make it difficult to get an accurate reading of respiratory movement and heart rate, which is drowned out by harmonics and noise signal interferences. To compensate for these interferences, this microradar system cross-references the in-phase (I) and quadrature-phase (Q) outputs of Doppler radar to recover target movement in real time. This cross-referencing of the two phases allows for identification and subsequent removal of non-linearity, providing accurate readings despite signal interferences.