Collimated Beam FMCW Radar for Vital Sign Patient Monitoring

Patient monitoring of vital signals such as breathing rhythm and heartbeat rate can be done remotely by the use of a radar system. This approach is advantageous since it does not require any contact with the patient. Obviously, contactless monitoring results in a more comfortable situation for the patient, and in occasions, it is almost mandatory as in the case of heavy burned or newborn patients. Moreover, additional information such movement patterns are also available. A 120 GHz frequency modulated continuous wave radar is described with special focus on the design, construction, and testing of a specific reflector antenna for the system. The system is based on a commercial radar chipset that includes its own antennas. The challenge has been to design the optimum reflector and to build it and test it in a cost-effective way. The reflector has been 3-D printed and a near-field testing technique has been implemented to assess its performance. The results show that the system is able to measure the vital signs at distances beyond 1 m.