Non-invasive measurement of laboratory rat's cardiorespiratory movement using a 60-GHz radar and nonlinear Doppler phase modulation

A non-invasive and non-contact monitoring system for measuring laboratory rat's cardiorespiratory movement is demonstrated. The system uses a 60-GHz CMOS radar integrated with antennas in a flip-chip package. Utilizing the harmonics generated in radar-detected signal due to the nonlinear phase modulation, the system can measure the displacements of respiration and heartbeat in addition to their frequencies. This is the first time that the simultaneous measurement of both displacements and frequencies of both respiration and heartbeat movements, by using a continuous-wave (CW) radar, is reported. Capable of measuring variations of both displacements and frequencies of respiration and heartbeat over time, the system can be useful for monitoring laboratory rat's vital signs without using implant devices.