In this paper, a low cost and low complexity Ultra- WideBand (UWB) RADAR system for distance measurement is presented as a first step for human breathing sensing. The emitter is based on Step Recovery and Schottky Diodes and delivers pulse signal with 230 ps width. The reflected signal by the target is recorded first on an oscilloscope and a further processing allows determining the target distance. After a calibration procedure, experimental results show a resolution of 5 cm and a maximum range of 45 cm. The oscilloscope is then replaced by a circuit named Time Delayed Sampling and Correlation (TDSC) and developed in our laboratory using a CMOS process. Experimental results show a resolution of 5 cm and a maximum range of 25 cm