4-Channel I/Q-Radar System For Vital Sign Monitoring In A Baby Incubator

With the system presented here a radar based sensor can be used to measure two vital signs, respiratory rate and heart rate, without the need of contact between patient and sensor. Operating at 24 GHz a frequency-modulated continuous-wave (FMCW) radar with a bandwidth of 250 MHz will be used. The antenna structure has been optimized to get a footprint just as big as the region of interest on the bed surface of the incubator. To measure the movement direction of the infants` chest, a branch-line coupler has been designed to get I- and Q-Signals. Based on the limited space inside of an incubator, a compact radar front end (RF-Front end) is developed by using microstrip line vias.